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Background: Pleural effusions are classified as exudate or transudate to guide clinical management. While Light’s criteria have been the standard for this differentiation due to their high sensitivity, their lower specificity can lead to potential misclassification of transudates as exudates. This study evaluates the clinical utility of pleural fluid cholesterol compared to Light’s criteria. Aims and Objectives: The aim of the study was to assess the clinical utility of pleural fluid cholesterol as a laboratory parameter in differentiating exudate from transudate pleural effusions. Materials and Methods: This cross-sectional study included 100 participants with pleural effusion. After baseline data collection and clinical examination, blood tests and pleural fluid analyses were conducted. McNemar’s test compared the sensitivity, specificity, and diagnostic accuracy of pleural fluid cholesterol with Light’s criteria. Results: Light’s criteria showed a sensitivity of 98.39%, specificity of 84.21%, positive predictive value (PPV) of 91.04%, negative predictive value (NPV) of 96.97%, and diagnostic accuracy of 93%. Pleural fluid cholesterol (threshold >45 mg/dL) demonstrated a sensitivity of 91.94%, specificity of 97.37%, PPV of 98.28%, NPV of 88.10%, and diagnostic accuracy of 94%. The difference in specificity was statistically significant (P

Background: Fifty years since its inception, Light's criteria have aided in classifying pleural effusions (PEs) as exudates if 1 or more criteria are met. Thoracic ultrasound (US) emerges as a non‐invasive technique for point of care use especially if pleural procedures are contemplated. Objective: We aimed to develop a score based on radiological and US features that could separate exudates from transudates without serum and pleural fluid biochemical tests necessary for Light's criteria. Methods: A prospective review of consecutive patients with PE who underwent thoracocentesis was performed. CXRs were evaluated for laterality followed by US for echogenicity, pleural nodularity, thickening and septations. PE was classified as exudate or transudate according to Light's criteria and corroborated with albumin gradient. A score combining radiological and US features was developed. Results: We recruited 201 patients with PE requiring thoracocentesis. Mean age was 64 years, 51% were females, 164 (81.6%) were exudates, and 37 (18.4%) were transudates. Assigning 1‐point for Diaphragmatic nodularity, Unilateral, Echogenicity, Pleural Thickening and Septations, DUETS ranged from 1 to 5. DUETS ≥2 indicated high likelihood for exudate (PPV 98.8%, NPV 100%) with 1% misclassification versus 6.9% using Light's criteria (p < 0.001). Conclusion: DUETS separated exudates from transudates with good accuracy, and could obviate paired serum and pleural fluid tests necessary for Light's criteria computation. Our study reflected real world practice where DUETS performed better than Light's criteria for PE that arose from more than one disease processes, and in the evaluation of patients with PE who have received diuretics. This study aimed to develop an accurate pleural ultrasound based composite score to accurately distinguish between transudates and exudates for clinical use, in evaluation of pleural effusions. The DUETS score was shown to accurately identify exudative effusions and would be particularly useful in clinical scenarios where there are dual pathologies. See relatededitorial [ABSTRACT FROM AUTHOR]

Background: Pleural effusions are classified as exudate or transudate to guide clinical management. While Light's criteria have been the standard for this differentiation due to their high sensitivity, their lower specificity can lead to potential misclassification of transudates as exudates. This study evaluates the clinical utility of pleural fluid cholesterol compared to Light's criteria. Aims and Objectives: The aim of the study was to assess the clinical utility of pleural fluid cholesterol as a laboratory parameter in differentiating exudate from transudate pleural effusions. Materials and Methods: This cross-sectional study included 100 participants with pleural effusion. After baseline data collection and clinical examination, blood tests and pleural fluid analyses were conducted. McNemar's test compared the sensitivity, specificity, and diagnostic accuracy of pleural fluid cholesterol with Light's criteria. Results: Light's criteria showed a sensitivity of 98.39%, specificity of 84.21%, positive predictive value (PPV) of 91.04%, negative predictive value (NPV) of 96.97%, and diagnostic accuracy of 93%. Pleural fluid cholesterol (threshold >45 mg/dL) demonstrated a sensitivity of 91.94%, specificity of 97.37%, PPV of 98.28%, NPV of 88.10%, and diagnostic accuracy of 94%. The difference in specificity was statistically significant (P<0.05), while the difference in sensitivity was not. The overall diagnostic accuracy of pleural fluid cholesterol was similar to that of Light's criteria. Conclusion: Pleural fluid cholesterol has a higher specificity and similar diagnostic accuracy compared to Light's criteria. It effectively identifies transudates, reduces false positives for exudates, and can serve as a simple test to confirm the type of pleural, potentially minimizing invasive procedures. [ABSTRACT FROM AUTHOR]

Biochemical parameters in the pleural fluid are commonly done to identify the cause of pleural effusion. Differentiating the effusion into either transudative or exudative is the preferential first step, with further investigating guided by the clinical features and these results. Light's criteria and other biochemical parameters help for differentiating the effusion. Not a single biochemical parameter will draw a conclusion of being the effusion as transudative or exudative, hence combining multiple biochemical tests will help to obtain a definitive diagnosis. Uric acid is one of the biochemical parameters utilised to identify the cause of effusion. This is the only biochemical parameter, which increases with statistical difference in transudates as compared to exudates, however, all other biochemical parameter increases in exudates as compared to transudates. We have done extensive search based on pertinent publication retrieved by a selective search in PubMed and on author's personal experience to know the usefulness of uric acid to differentiate between transudates and exudates. We concluded that, uric acid is useful for differentiation of effusions, however, extensive research with inclusion of a greater number of patients is essential to draw the conclusion. [ABSTRACT FROM AUTHOR]

Persistent pleural effusions (PPEf) represent a known complication of orthotopic liver transplant (OLT). However, their clinical relevance is not well described. We evaluated the clinical, biochemical, and cellular characteristics of post-OLT PPEf and assessed their relationship with longitudinal outcomes. We performed a retrospective cohort study of OLT recipients between 2006 and 2015. Included patients had post-OLT PPEf, defined by effusion persisting >30 days after OLT and available pleural fluid analysis. PPEf were classified as transudates or exudates (ExudLight) by Light's criteria. Exudates were subclassified as those with elevated lactate dehydrogenase (ExudLDH) or elevated protein (ExudProt). Cellular composition was classified as neutrophil- or lymphocyte-predominant. Of 1602 OLT patients, 124 (7.7%) had PPEf, of which 90.2% were ExudLight. Compared to all OLT recipients, PPEf patients had lower two-year survival (HR 1.63; p = 0.002). Among PPEf patients, one-year mortality was associated with pleural fluid RBC count (p = 0.03). While ExudLight and ExudProt showed no association with outcomes, ExudLDH were associated with increased ventilator dependence (p = 0.03) and postoperative length of stay (p = 0.03). Neutrophil-predominant effusions were associated with increased postoperative ventilator dependence (p = 0.03), vasopressor dependence (p = 0.02), and surgical pleural intervention (p = 0.02). In summary, post-OLT PPEf were associated with increased mortality. Ninety percent of these effusions were exudates by Light's criteria. Defining exudates using LDH only and incorporating cellular analysis, including neutrophils and RBCs, was useful in predicting morbidity.

Introduction: Pleural effusions are known to occur in many cases of COVID‐19. Data on typical characteristics of COVID‐19‐associated pleural effusions are limited. The goal of this project was to characterize the pleural fluid from patients with COVID‐19. Methods: We retrospectively collected electronic medical record data from adults hospitalized at a large metropolitan hospital system with COVID‐19 infection who had a pleural effusion and a thoracentesis performed. We assessed pleural fluid characteristics and applied Light's criteria. Results: We identified 128 effusions from 106 unique patients; 45.4% of the effusions had fluid/serum protein ratio greater than 0.5, 33.9% had fluid/serum lactate dehydrogenase (LDH) greater than 0.6, and 56.2% had fluid LDH greater than 2/3 of the serum upper limit of normal. Altogether, 68.5% of effusions met at least one of these three characteristics and therefore were exudative by Light's criteria. The white blood cell (WBC) differential was predominantly lymphocytic (mean 42.8%) or neutrophilic (mean 28.7%); monocytes (mean 12.7%) and eosinophils (mean 2.5%) were less common. Conclusion: We demonstrate that 68.5% of pleural effusions in patients with COVID‐19 infection were exudative and hypothesize that COVID‐19‐associated pleural effusions are likely to be exudative with WBC differential more likely to be predominantly lymphocytic. [ABSTRACT FROM AUTHOR]

Introduction: Aim of this study is to compare COSTA’S and LIGHT’S criteria in identifying exudative from transudative pleural effusions.Materials & Methods: A prospective study that is hospital-based was conducted at GHCCD, during Jan 2017 to August 2018 in 80 patients who presented with pleural effusion. Light’s and Costa’s criteria were applied to differentiate them into transudative and exudative effusions.Results: Among the pleural effusions, 83.75% were exudates and 16.25% were transudates. Tuberculous effusion (45%) was the most common among exudates, and chronic kidney disease (10%) was the most common among the transudates. On biochemical analysis of effusions, the mean pleural fluid cholesterol levels were 74.02±20.51mg/dl and 29.23±7.44mg/dl in exudative and transudative effusions respectively. On ROC analysis, the cut-off value for pleural fluid cholesterol was considered >50mg/dl and 231U/L for exudative effusions and

Simple Summary: Analysis and classification of effusions is helpful in guiding diagnostic tests to identify an underlying disease. The traditional veterinary classification of effusions does not adequately reflect the disease mechanism causing the effusion in cats and might not sufficiently inform diagnostic work-up. The aim of this study was to assess whether other parameters might aid classification. Sixty-five cats with body cavity effusions (within the abdomen, chest and pericardial sac) were included. Effusions were classified as transudates (e.g., heart failure [n = 18]) or exudates (e.g., inflammation, cancer [n = 47]) based on the disease mechanism causing the effusion, and using the traditional scheme. Several parameters (activity of enzyme lactate dehydrogenase in the effusion; effusion/serum ratio of the enzymatic activity of lactate dehydrogenase; effusion/serum total protein ratio; serum–effusion albumin gradient; acute phase proteins in serum and effusion) were analysed in their ability to differentiate exudates from transudates. All tested parameters performed better in classifying effusions in comparison to the traditional scheme. Acute phase proteins were helpful in classifying effusions based on their disease mechanism but could not separate effusion types when using the traditional scheme. This latter finding further supports the classification of effusions based on their disease mechanism. Better classification of effusions might improve disease diagnosis in the future. The traditional veterinary classification (TVC) of effusions based on cell count and total protein (TP) does not adequately reflect the aetiology. Light's criteria (LC) (activity of lactate dehydrogenase [LDH] in the effusion [LDHef], effusion/serum LDH ratio [LDHr], effusion/serum TP ratio [TPr]), serum–effusion albumin gradient (ALBg), acute phase proteins (APPs) [serum amyloid A (SAA), α1-acid glycoprotein (AGP), haptoglobin] might aid classification. The aim was to evaluate the utility of these parameters except LDHr in differentiating exudates from transudates. Sixty-five cats with effusions (33 peritoneal, 31 pleural, 1 pericardial), with 18 transudates and 47 exudates based on aetiological classification (AC), were included. The sensitivity, specificity and accuracy of several parameters to identify exudates (based on AC) was assessed. APPs were compared between exudates and transudates based on AC and TVC, with receiver operating characteristics analysis identifying the best APP to recognise exudates. Simplified LC (LDHef, TPr) had an accuracy of 79% and TVC of 48%. ALBg had the highest sensitivity (98%) and LDHef the highest specificity (83%) in identifying exudates in cats. All APPs but effusion SAA could differentiate exudates from transudates based on AC (effusion AGP had the largest area under the curve 0.79) but not TVC. All parameters were better than TVC in identifying exudates. The conformity of APPs with AC but not TVC favours the use of AC to classify effusions. [ABSTRACT FROM AUTHOR]

Introduction: While Light's criteria exhibit high sensitivity (98%) in detecting exudative pleural effusions, the capacity to rule out transudates is relatively limited. A previous study showed that approximately one-fifth of patients with congestive cardiac failure on diuretics also met the criteria for exudate. This study compares the diagnostic value of Light's criteria, the serum-effusion albumin gradient (SEAG) method, and pleural effusion glucose levels for accurately categorizing pleural effusion as transudate or exudate. Methodology: We conducted this cross-sectional observational study in a tertiary care hospital in Ahmedabad, India. Two hundred patients with pleural effusion undergoing thoracentesis were included. Laboratory parameters measured in pleural fluid analysis included pleural fluid protein, pleural fluid lactate dehydrogenase (LDH), pleural fluid albumin, and pleural fluid glucose. Serum protein, serum LDH, and serum albumin were also collected. Mean values and standard deviations (SDs) were calculated for analysis. Results: A significant difference was observed in the mean value of exudative and transudative effusions for each parameter (pleural fluid protein/serum fluid protein ratio, pleural fluid LDH/serum fluid LDH ratio, pleural fluid LDH, SEAG, and pleural fluid glucose) (P < 0.001). Light's criteria demonstrated the highest efficacy in diagnosing exudates (accuracy = 97.50%), while SEAG demonstrated the highest efficacy in diagnosing transudates (accuracy = 97.50%). [ABSTRACT FROM AUTHOR]

See relatedarticle [ABSTRACT FROM AUTHOR]

Introduction: Light's criteria had been the standard method for distinguishing exudative and transudative pleural effusions which misidentify 15-20% of transudates as exudates. This study aims to find out the role of combined pleural fluid cholesterol and total protein in distinguishing exudative from transudative pleural effusions and its applicability in Nepalese populations. Materials and Methods: Patients with pleural effusions were enrolled for the study. The combined pleural fluid cholesterol and total protein were compared with Light’s criteria and also compared with the diagnosis on discharge to find out their usefulness in categorizing the pleural effusions. Results: A total of 81 patients enrolled in the study, 42 (51.9%) were male. Based on Light’s criteria, 88.8% pleural effusions were found to be exudates and 11.1% were found to be transudates. Within the criteria, Light’s criteria categorized more pleural fluids as exudates than the diagnosis on discharge. Based on pleural fluid cholesterol >60mg/dL and protein >3g/dL for the classification of exudative and transudative pleural fluid, 62.9% out of 81 samples felled under the exudates and 37.03% pleural effusions under transudates with the sensitivity 87.9% and specificity 100%. Conclusions: Though Light’s criteria remain the gold standard to differentiate transudates and exudates, combined pleural fluid cholesterol and total protein give nearly comparable results without the need for simultaneous blood investigations.

Persistent pleural effusions (PPEf) represent a known complication of orthotopic liver transplant (OLT). However, their clinical relevance is not well described. We evaluated the clinical, biochemical, and cellular characteristics of post-OLT PPEf and assessed their relationship with longitudinal outcomes. We performed a retrospective cohort study of OLT recipients between 2006 and 2015. Included patients had post-OLT PPEf, defined by effusion persisting >30 days after OLT and available pleural fluid analysis. PPEf were classified as transudates or exudates (ExudLight) by Light’s criteria. Exudates were subclassified as those with elevated lactate dehydrogenase (ExudLDH) or elevated protein (ExudProt). Cellular composition was classified as neutrophil- or lymphocyte-predominant. Of 1602 OLT patients, 124 (7.7%) had PPEf, of which 90.2% were ExudLight. Compared to all OLT recipients, PPEf patients had lower two-year survival (HR 1.63; p = 0.002). Among PPEf patients, one-year mortality was associated with pleural fluid RBC count (p = 0.03). While ExudLight and ExudProt showed no association with outcomes, ExudLDH were associated with increased ventilator dependence (p = 0.03) and postoperative length of stay (p = 0.03). Neutrophil-predominant effusions were associated with increased postoperative ventilator dependence (p = 0.03), vasopressor dependence (p = 0.02), and surgical pleural intervention (p = 0.02). In summary, post-OLT PPEf were associated with increased mortality. Ninety percent of these effusions were exudates by Light’s criteria. Defining exudates using LDH only and incorporating cellular analysis, including neutrophils and RBCs, was useful in predicting morbidity.

Context: The incidence of pleural effusion is approximately one million per year. For diagnosing and treatment plan, pleural effusions have to be classified into transudate and exudate. If the diagnosis is not appropriate, it may result in severe complications. The established criterion for differentiating exudates from transudates is Light's criteria. But there were some false positive results in case of transudative effusions when Light's criteria were used. Aims: This study was done to determine the accuracy of serum effusion albumin gradient (SEAG) when compared to Light's criteria in differentiating transudates and exudates. Settings and Design: It is a prospective observational study. In the present study, the sample size is 66 patients, in whom the SEAG was used for the classification of pleural effusions with a cut-off value of 1.2 g/dl. Methods and Materials: All the blood samples were collected and biochemical parameters like total protein, albumin, and LDH were analyzed in both serum and pleural fluid using XL 640 fully automated random access analyzer. Statistical Analysis Used: Results were analyzed using SPSS software version 20. Results: 20 of 22 transudates and 41 of 44 exudates were classified correctly using SEAG. The diagnostic accuracy of SEAG (92.42%) is better than Light's criteria (87.87%) in differentiating both transudative and exudative effusions. Conclusions: The SEAG is superior to Light's criteria in identifying the transudative effusions. It is also observed that Light's criteria identified exudative effusions better than SEAG.

Context: The incidence of pleural effusion is approximately one million per year. For diagnosing and treatment plan, pleural effusions have to be classified into transudate and exudate. If the diagnosis is not appropriate, it may result in severe complications. The established criterion for differentiating exudates from transudates is Light's criteria. But there were some false positive results in case of transudative effusions when Light's criteria were used. Aims: This study was done to determine the accuracy of serum effusion albumin gradient (SEAG) when compared to Light's criteria in differentiating transudates and exudates. Settings and Design: It is a prospective observational study. In the present study, the sample size is 66 patients, in whom the SEAG was used for the classification of pleural effusions with a cut-off value of 1.2 g/dl. Methods and Materials: All the blood samples were collected and biochemical parameters like total protein, albumin, and LDH were analyzed in both serum and pleural fluid using XL 640 fully automated random access analyzer. Statistical Analysis Used: Results were analyzed using SPSS software version 20. Results: 20 of 22 transudates and 41 of 44 exudates were classified correctly using SEAG. The diagnostic accuracy of SEAG (92.42%) is better than Light's criteria (87.87%) in differentiating both transudative and exudative effusions. Conclusions: The SEAG is superior to Light's criteria in identifying the transudative effusions. It is also observed that Light's criteria identified exudative effusions better than SEAG. [ABSTRACT FROM AUTHOR]

Biochemical parameters in pleural fluid are usually done to identify the cause of pleural effusion. Differentiating the effusion into either transudative or exudative is a logical first step, with further investigations dictated by the clinical features and these results. Light’s criteria and other biochemical parameters help to obtain a result for differentiating the effusion. Not a single laboratory value will draw a conclusion of being the effusion as transudative or exudative, hence combining number of biochemical test will help to obtain a definitive result. Pleural glucose measurement is routine and age old parameter used to identify cause of pleural effusion. In this review we tried to evaluate the usefulness of pleural glucose in effusion. In country like India, where all routine and specialized biochemical parameters may not be available for identifying the specific cause of effusion, the estimation of pleural glucose may help to draw an initial approach for classifying an effusion.

Purpose: To describe a case of a patient with acute systemic lupus erythematous (SLE) causing choroidal effusions and to report a novel technique for evaluation of the choroidal fluid which sheds light on effusion pathogenesis. Observations: A 37 year-old woman was referred for decreased vision, eye pain and shortness of breath. The patient had bilateral angle closure glaucoma from choroidal effusions and bilateral pleural effusions. Work-up revealed new onset acute SLE. A technique for obtaining suprachoroidal fluid is described, and the fluid was analyzed using Light's criteria and found to be exudative in nature. Conclusions and importance: There has been speculation as to pathogenesis of choroidal effusions in a variety of conditions, and many authors believe the most likely process to be transudative. The exudative nature of the fluid in our patient suggests that choroidal effusions in acute SLE are likely caused by inflammation, and not secondary to hypoalbuminemia or another transudative process. Similar analyses of suprachoroidal fluid in other disease processes may help elucidate the underlying pathogenesis and may possibly guide treatment.

Background: An important part of the investigation of pleural effusion is the identification of markers that help separate exudate from transudate. Objectives: The purposes of this study were to compare the accuracy of published and new sets of criteria to distinguish between exudative and transudative pleural effusions, and to determine whether serum biochemical analysis is necessary. Methods: An externally validated cohort study was performed. Pleural effusions were determined to be transudative or exudative on the basis of an assessment of the medical record by two clinicians blinded to biochemical results. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the receiver operating characteristic curve were determined for each proposed combination of criteria. Results: Pleural fluid analysis was available for 311 thoracenteses in the main cohort and for 112 thoracenteses in the validation cohort. The best sensitivity (97% [95% CI 94–99]) and negative likelihood ratio (0.04 [95% CI 0.02–0.08]) for identifying exudative effusions were observed with criteria combining pleural fluid lactate dehydrogenase greater than 0.6 the upper limit of normal serum lactate dehydrogenase and pleural fluid cholesterol greater than 1.04 mmol/L (40 mg/dL). The overall diagnostic accuracy was similar to Light's criteria. Findings were similar in the validation cohort. Conclusions: Our proposed criteria using simultaneously pleural fluid lactate dehydrogenase and pleural fluid cholesterol can identify an exudate with a sensitivity and an overall diagnostic accuracy similar to Light's criteria. It avoids simultaneous blood sampling, thus reducing patient discomfort and potential costs. [ABSTRACT FROM AUTHOR]

Background Chemistry testing is requested for body fluid (BF) specimens despite the lack of assays approved by the US Food and Drug Administration (FDA). The criteria for categorizing fluids as transudate or exudate are not validated across analyzers. Objective To compare BF chemical analysis and classification by different analyzers. Methods We analyzed 10 pleural and 18 peritoneal fluids with corresponding plasma specimens using the Vitros 5,1 FS; Abbott ARCHITECT ci8200; and Roche Modular P platforms. Total protein (TP) and lactate dehydrogenase (LDH) were measured for pleural fluids. Light's criteria were applied. Albumin was measured for peritoneal specimens, and the plasma-ascites-albumin gradient was calculated. Results TP results showed agreement. The Vitros LDH assay produced higher fluid:plasma ratios. Classification by Light's criteria resulted in 1 discrepancy (ARCHITECT). Albumin results showed agreement. There were 2 discrepant gradient interpretations (Vitros). Conclusions These data suggest that analyses of pleural and peritoneal fluids using these platforms are diagnostically interchangeable. [ABSTRACT FROM AUTHOR]

A 62-year-old female presented to the emergency room with one-month history of epigastric abdominal pain, nausea and vomiting. She endorsed progressive dyspnea over two weeks. CT of the abdomen demonstrated bilateral pleural effusions and pancreatic inflammation, so the working diagnosis was pancreatitis. A diagnostic thoracentesis was performed and the pleural fluid analysis was classified as transudate by Light's criteria. Given the atypical features in history and concern for malignancy, fluid was sent for cytological examination and immunohistochemistry which suggested a mucinous malignancy. EGD revealed poorly differentiated signet ring cell adenocarcinoma of stomach. Patient underwent placement of indwelling pleural catheters for symptomatic improvement and was discharged to hospice. The decision whether to routinely send transudative effusions for cytological evaluation remains controversial. This case demonstrates the importance of using clinical judgement to guide that decision.

Background: In pleural effusion, differentiating exudative and transudative fluid is an important clinical evaluation. The objective of the study was to determine the efficacy of pleural fluid serum bilirubin ratio in differentiating exudative and transudative effusions. In resource-limited settings with no facilities to measure lactate dehydrogenase (LDH) levels, using pleural fluid bilirubin ratio may help in better clinical decision. Methods: It was a prospective observational study, conducted in the emergency department of Tribhuvan University Teaching Hospital. All the patients attending for emergency care with pleural effusion from 6th Jan 2015 to 5th Jan 2016 were included. The cases were divided as exudates and transudates on basis of final diagnosis. Serum and pleural fluid specimen were collected and sent for investigations. The data for various laboratory parameters especially those of lights criteria and bilirubin ratio were then analyzed and fluid nature was compared with results from parameters and final diagnoses. Results: Among 103 cases, 71.84% had exudate and 28.16% had transudate. The commonest cause of effusion was pneumonia 35.92%, second being tubercular 23.30% followed by malignant effusion 12.60%, congestive heart failure 11.65%, chronic kidney disease 10.67% and liver cirrhosis 5.82%. The mean bilirubin ratio for exudates exceeded that for transudates. Considering the cutoff point of 0.6, the sensitivity, specificity, positive predictive value and negative predictive value were respectively 88.00%, 93.00%, 97.00% & 75.00%. Conclusions: Pleural fluid serum bilirubin ratio can be utilized as a diagnostic tool for differentiating exudative and transudative effusions. Keywords: bilirubin ratio; exudates; light’s criteria; pleural effusion; transudates.

Background: Pleural fluid biochemical analysis is the first step in pleural effusion (PE) diagnostics. Our purpose was to analyse the utility of the biomarkers used at our clinic in the routine diagnosis of PE. Methods: We retrospectively reviewed the PE levels of proteins, lactate dehydrogenase (LDH), alpha amylase (AA), pH and glucose in 433 patients who were treated at the University Clinic Golnik in a one-year period and compared these values with the final identified aetiology of the effusions. Results: The majority of the effusions were determined to be a consequence of malignancy (n = 154) or infection (n = 108). In 94 cases the aetiology of the effusions was heart failure and in 54 cases other diseases, while 23 effusions remained aetiologically undetermined. Considering Light’s criteria, the vast majority of the effusions were correctly classified as exudates or transudates (97.1 %). Comparing paramalignant and malignant effusions, we detected significantly lower values of pleural fluid LDH (p < 0.0005) and proteins (p < 0.0005), and higher pH (p < 0.0005) values in the paramalignant effusions. Conclusion: We have found that pleural LDH and proteins are the most helpful biochemical parameters in our routine diagnosis of pleural effusions and helped us to correctly narrow the aetiological spectrum. Furthermore, significantly higher pleural LDH and protein values and a pH below 7.32 additionally facilitated distinguishing between malignant and paramalignant effusions. Parameters such as glucose and AA are useful in selected cases and have a limited role in routine diagnostics.

Background Pleural effusions are classified into transudates and exudates based on Light’s criteria, but the main disadvantage of Light’s criteria is the misclassification of transudates as exudates in about 20% of cases. The aim of this study was to determine the validity of various biochemical parameters to differentiate pleural exudates and transudates. Methods An observational study to evaluate diagnostics tests was conducted at the emergency department of Persahabatan Hospital, Jakarta, from September 2010 until December 2011. In total, 119 patients with pleural effusion were evaluated. Simultaneous pleural effusion and blood samples were examined for lactate dehydrogenase (LDH), total protein, cholesterol and albumin, with the clinical diagnosis as the gold standard. Results There were 104 exudative and 15 transudative pleural effusions. Light’s criteria achieved a higher overall accuracy (sensitivity 97%, specificity 80%, accuracy 95%). The optimum cut off values were pleural fluid to serum ratio of LDH 0.4 (sensitivity 95%, specificity 87%, accuracy 94%) and pleural fluid LDH of 178 IU/L (sensitivity 92%, specificity 87%, accuracy 92%). Pleural fluid cholesterol was 50 mg/dL (sensitivity 89%, specificity 53%, accuracy 85%), pleural fluid to serum cholesterol ratio 0.41 (sensitivity 75%, specificity 53%, accuracy 72%) and serum-effusion albumin gradient 1.3 g/dL (sensitivity 91%, specificity 73%, accuracy 89%). Combination of biochemical tests did not improve sensitivity or accuracy. Conclusions Light’s criteria remain superior to other biochemical tests, but the new cut off values of LDH pleural fluid to serum ratio of 0.4 and pleural fluid LDH of 178 IU/L appears to yield a slight improvement in diagnostic accuracy.

Pleural or abdominal effusions are frequent findings in ICU and Internal Medicine patients. Diagnostic gold standard to distinguish between transudate and exudate is represented by "Light's Criteria," but, unfortunately, the chemical-physical examination for their calculation is not a rapid test. Pursuing an acid-base assessment of the fluid by a blood-gas analyzer, an increase of lactate beyond the normal serum range is reported in the exudative effusions. The advantages of this test are that it is a very fast bed-side test, executable directly by the physician. The aim of this study is to evaluate whether the increase in lactate in pleural and abdominal effusions might be used as a criterion for the differential diagnosis of the nature of the fluid. Sixty-nine patients with pleural or abdominal effusions and clinical indication for thoracentesis or paracentesis were enrolled. Acid-base assessment with lactate, total protein, and LDH dosage on the serum, and acid-base assessment with lactate, total protein, and LDH dosage, cytology, and bacterial culture on the fluid were performed to each patient. Fluid-blood lactate difference (ΔLacFB) and fluid-blood lactate ratio (LacFB ratio) were calculated. A statistical analysis was carried out for fluid lactate (LacF), ΔLacFB, and LacFB ratio, performing ROC curves to find the cut-off values with best sensitivity (Sn) and specificity (Sp) predicting an exudate diagnosis: LacF: cut-off value: 2.4 mmol/L; AU-ROC 0.854 95% CI 0.756-0.952; Sn 0.77; Sp 0.84. ΔLacFB: cut-off value: 0.95 mmol/L; Au-ROC 0.876 95% CI 0.785-0.966; Sn 0.80; Sp 0.92. LacFB ratio: cut-off value: 2 mmol/L; Au-ROC 0.730 95% CI 0.609-0.851; Sn 0.74; Sp 0.65. Lactate dosage by blood-gas analyzer on pleural and abdominal effusions seems to be a promising tool to predict a diagnosis of exudate. [ABSTRACT FROM AUTHOR]

Pneumonia is an important health problem in children, and parapneumonic pleural effusion (PPE) is a frequent complication. There is no standard strategy for treating PPE, reflected in the few international guidelines that have been published on the issue. Compared to adults, there is no consensus on the utility of pleural fluid analysis in paediatric PPE. This is because of the lack of good evidence either in favour or against it and the risks of procedural sedation for acquiring pleural fluid for analysis to guide management. In this paper we provide a succinct review of the different approaches to the management of PPE, including diagnosis, pleural fluid analysis (Light’s criteria) and treatment, both medical and surgical. [ABSTRACT FROM AUTHOR]

Background: Pleural effusion is the one of the most common Respiratory diseases admitted in the medical ward, most often diagnosed by clinical, radiological and pleural fluid analysis. Materials and methods: This was a cross-sectional study conducted in Government Royapettah hospital in the Department of Medicine during the period January 2016 to August 2016. Patients admitted as in-patients in medical wards and newly diagnosed to have pleural effusion clinically and radiologically were included in the study. Results: 10 cases out of fifty cases in the study were below the age of thirty years comprising 20% of total cases. 17 cases between 31-40 years comprised 34% of total cases. Lymphocytic pleural effusion was 21 cases out of 50 cases comprising 42%. Conclusion: Pleural fluid cholesterol and LDH test is useful to differentiate pleural fluid exudate and transudate with the advantage of requiring only two laboratory parameters and no simultaneous blood sample especially in countries like India, with financial and technical constraints. [ABSTRACT FROM AUTHOR]

Background: Light′s criteria is the gold standard to differentiate transudative pleural effusion (PE) from exudative PE, but it requires four biochemical estimations which, in developing countries such as India, may not be feasible in every patient due to economic constraints. Aims: To evaluate the comparative usefulness of pleural fluid biochemical parameters with relative usefulness of pleural cholesterol to the traditional Light′ criteria. Setting and Design: Prospective institutional based study. Materials and Methods: A total of 56 cases of PE were studied consecutively, of which 34 cases were of tuberculous effusion and 22 cases of nontubercular effusion. The data obtained from the patients were collected, analyzed, and observations noted down. Statistical Analysis: Sensitivity, specificity, positive predictive value and negative predictive value of different biochemical parameters single or in combination were analyzed by SPSS 16 software. Results: According to their etiology, 7 of the effusions were transudates and 49 were exudates. Using a cutoff point of 45 mg for pleural cholesterol and values for protein and lactate dehydrogenase (LDH) of Light et al., the best diagnostic power corresponded to the combination of pleural cholesterol and LDH; cholesterol level over 45 mg/dL and/or LDH over 200 IU/L differentiate exudates from transudates with a sensitivity of 99% and a specificity of 98%. Conclusions: The measurement of pleural cholesterol and LDH permits the separation of pleural exudates from transudates with accuracy similar to the original report of Light et al., with the advantage of requiring only two laboratory determinations and no simultaneous blood sample, especially in a country like India where financial and technical constraints are immense.

Background Pleural effusions are classified into transudates and exudates based on Light’s criteria, but the main disadvantage of Light’s criteria is the misclassification of transudates as exudates in about 20% of cases. The aim of this study was to determine the validity of various biochemical parameters to differentiate pleural exudates and transudates. Methods An observational study to evaluate diagnostics tests was conducted at the emergency department of Persahabatan Hospital, Jakarta, from September 2010 until December 2011. In total, 119 patients with pleural effusion were evaluated. Simultaneous pleural effusion and blood samples were examined for lactate dehydrogenase (LDH), total protein, cholesterol and albumin, with the clinical diagnosis as the gold standard. Results There were 104 exudative and 15 transudative pleural effusions. Light’s criteria achieved a higher overall accuracy (sensitivity 97%, specificity 80%, accuracy 95%). The optimum cut off values were pleural fluid to serum ratio of LDH 0.4 (sensitivity 95%, specificity 87%, accuracy 94%) and pleural fluid LDH of 178 IU/L (sensitivity 92%, specificity 87%, accuracy 92%). Pleural fluid cholesterol was 50 mg/dL (sensitivity 89%, specificity 53%, accuracy 85%), pleural fluid to serum cholesterol ratio 0.41 (sensitivity 75%, specificity 53%, accuracy 72%) and serum-effusion albumin gradient 1.3 g/dL (sensitivity 91%, specificity 73%, accuracy 89%). Combination of biochemical tests did not improve sensitivity or accuracy. Conclusions Light’s criteria remain superior to other biochemical tests, but the new cut off values of LDH pleural fluid to serum ratio of 0.4 and pleural fluid LDH of 178 IU/L appears to yield a slight improvement in diagnostic accuracy.

Introduction While Light's criteria exhibit high sensitivity (98%) in detecting exudative pleural effusions, the capacity to rule out transudates is relatively limited. A previous study showed that approximately one-fifth of patients with congestive cardiac failure on diuretics also met the criteria for exudate. This study compares the diagnostic value of Light's criteria, the serum-effusion albumin gradient (SEAG) method, and pleural effusion glucose levels for accurately categorizing pleural effusion as transudate or exudate. Methodology We conducted this cross-sectional observational study in a tertiary care hospital in Ahmedabad, India. Two hundred patients with pleural effusion undergoing thoracentesis were included. Laboratory parameters measured in pleural fluid analysis included pleural fluid protein, pleural fluid lactate dehydrogenase (LDH), pleural fluid albumin, and pleural fluid glucose. Serum protein, serum LDH, and serum albumin were also collected. Mean values and standard deviations (SDs) were calculated for analysis. Results A significant difference was observed in the mean value of exudative and transudative effusions for each parameter (pleural fluid protein/serum fluid protein ratio, pleural fluid LDH/serum fluid LDH ratio, pleural fluid LDH, SEAG, and pleural fluid glucose) (P < 0.001). Light's criteria demonstrated the highest efficacy in diagnosing exudates (accuracy = 97.50%), while SEAG demonstrated the highest efficacy in diagnosing transudates (accuracy = 97.50%). Conclusion SEAG is an effective alternative diagnostic tool for identifying transudates misclassified by Light's criteria. Its use can contribute to prompt diagnosis and timely treatment of patients with pleural effusion, improving patient outcomes., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Sharma et al.)

Light's criteria falsely label a significant number of effusions as exudates. Such exudative effusions with transudative etiologies are referred to as "pseduoexudates". In this review, we discuss a practical approach to correctly classify an effusion that may be a pseudoexudate. A PubMed search yielded 1996 manuscripts between 1990 and 2022. Abstracts were screened and 29 relevant studies were included in this review article. Common etiologies for pseudoexudates include diuretic therapy, traumatic pleural taps, and coronary artery bypass grafting. Here, we explore alternative diagnostic criteria. Concordant exudates (CE), defined as effusions where proteins in pleural fluid/serum (PF/SPr) > 0.5 and pleural fluid LDH level of >160 IU/L (>2/3 upper limit of normal) confer higher predictive value to the Light's criteria. Serum-pleural effusion albumin gradient (SPAG) > 1.2 g/dL and serum-pleural effusion protein gradient (SPPG) > 3.1 g/dL together yielded a sensitivity of 100% in heart failure and a sensitivity of 99% in hepatic hydrothorax whe n identifying pseudoexudates (Bielsa et al., 2012) [5]. Pleural fluid N-Terminal Pro Brain Natriuretic Peptide (NTPBNP) offered a specificity and sensitivity of 99% in identifying pseudoexudates when using a cut-off of >1714 pg/mL (Han et al., 2008) [24]. However, its utility remains questionable. Additionally, we also looked at pleural fluid cholesterol and imaging modalities such as ultrasound and CT scan to measure pleural thickness and nodularity. Finally, the diagnostic algorithm we suggest involves using SPAG >1.2 g/dL and SPPG >3.1 g/dL in effusions classified as exudates when there is a strong clinical suspicion for pseudoexudates., Competing Interests: Declaration of competing interest All authors declare that they have no conflicts of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Light's criteria are the cornerstone to differentiate exudates from transudates. The traditional literature states that malignant pleural effusions are rarely transudative; therefore, cytology tends to be low yield and not a cost-effective decision. This case describes an 82-year-old female who developed a transudative pleural effusion despite having an underlying malignancy, highlighting the importance of integrating clinical judgment into pursuing thoracentesis with the cytological examination., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Cardenas Ramos et al.)

A 62-year-old female presented to the emergency room with one-month history of epigastric abdominal pain, nausea and vomiting. She endorsed progressive dyspnea over two weeks. CT of the abdomen demonstrated bilateral pleural effusions and pancreatic inflammation, so the working diagnosis was pancreatitis. A diagnostic thoracentesis was performed and the pleural fluid analysis was classified as transudate by Light's criteria. Given the atypical features in history and concern for malignancy, fluid was sent for cytological examination and immunohistochemistry which suggested a mucinous malignancy. EGD revealed poorly differentiated signet ring cell adenocarcinoma of stomach. Patient underwent placement of indwelling pleural catheters for symptomatic improvement and was discharged to hospice. The decision whether to routinely send transudative effusions for cytological evaluation remains controversial. This case demonstrates the importance of using clinical judgement to guide that decision. [ABSTRACT FROM AUTHOR]

Objective: To assess the efficacy of pleural fluid cholesterol in differentiating transudates and exudates as compared with Light’s criteria. Methods: Patients with pleural effusion during a 6-month period were enrolled in the study and underwent thoracentesis. Pleural fluid was analyzed for the levels of protein, lactate dehydrogenase (LDH), and cholesterol. Etiological diagnosis, which was established after considering clinical and biochemical factors, was the gold standard for comparison. Cut-off values for pleural fluid cholesterol were taken as 60 mg/dL and 45 mg/dL. Results: A total of 53 patients were included for final analysis. Of them, 19 were with transudates and 34 with exudates in their pleural fluids. The sensitivity, specificity, positive predictive value, and negative predictive value of the pleural fluid cholesterol (cut-off >45 mg/dL) were 97.06%, 94.74%, 97.06%, and 94.74%, respectively, for identifying exudates. These values were differentiating better than those obtained by Light’s criteria for pleural fluid cholesterol (cut-off >60 mg/dL) (p<0.0001). Combining pleural fluid protein with pleural fluid cholesterol (>45 mg/dL) gave a higher specificity (100%) and positive predictive value (100%) but a lower sensitivity (82.93%) and negative predictive value (63.16%). Conclusion: Pleural fluid cholesterol is better than Light’s criteria for the differentiation of transudates and exudates and is less cumbersome as it does not require a simultaneous blood sampling. Cut-off value of pleural fluid cholesterol for differentiating transudates and exudates should be 45 mg/dL. Further studies are warranted to assess the efficacy of the combination of pleural fluid protein and cholesterol as criteria for classifying effusions. [ABSTRACT FROM AUTHOR]

The objective of present study was to evaluate the efficacy of pleural fluid alkaline phosphatase and its ratio to serum levels to classify pleural fluids. A total of 80 patients were divided in transudates and exudates on the basis of extensive clinical, radiological and biochemical evaluation. The efficacy of pleural fluid alkaline phosphatase (P ALP) and pleural fluid / serum alkaline phosphatase ratio (P/S ALP) assessment along with that of Light′s criteria to accurately classify transudates and exudates were analyzed. Up to 89% transudates misclassified by Light′s criteria were correctly classified by pleural fluid alkaline phosphatase (P ALP) and pleural fluid/serum alkaline phosphatase ratio (P/S ALP) evaluation. Similarly 92% exudates misclassified by Light′s criteria were correctly classified by pleural fluid alkaline phosphatase (P ALP) and pleural fluid/serum alkaline phosphatase ratio (P/S ALP) evaluation. By applying a cut off value of 40.0 IU for P ALP, a sensitivity of 85% and specificity of 75% was found. For P/S ALP, applying a cut off value of 0.25 a sensitivity of 85% and specificity of 80% was found. Both P ALP and P/S ALP had a PPV of 92%. However, their respective NPV were 63% and 70%.

Pleural effusions are common in hemodialysis patients and are associated with significant morbidity. Diagnostic pleural aspiration and subsequent biochemical analysis can be used to differentiate exudates and transudates. In particular, Light's criteria have been validated in the general population although their efficacy in hemodialysis patients is unclear. Furthermore, aspiration is not without risk; we report the case of a life-threatening thoracic bleed as a complication of diagnostic thoracocentesis in a hemodialysis patient, in whom a transudative effusion was misclassified according to Light's criteria. Retrospective examination of a further 22 aspirations in hemodialysis patients suggests that biochemical analysis of pleural fluid in this group is of limited value. Careful clinical and radiological assessment may be of greater value in determining individuals who may benefit from formal drainage, rather than diagnostic aspiration with its attendant risks. [ABSTRACT FROM AUTHOR]

Background: Pleural effusions are most commonly classified as transudative or exudative based on Light's criteria which has shown misclassification in 10%-20% of cases. Studies have demonstrated lesser misclassification with pleural fluid cholesterol criteria. Thus, this study aimed to find the diagnostic properties of pleural fluid cholesterol in differentiating the type of effusion., Materials and Methods: This cross-sectional study involving 72 patients was undertaken in a tertiary center in Nepal for a duration of 2 years. On the basis of Light's, Heffner's, etiological, and pleural fluid cholesterol criteria, pleural effusion was classified as exudative or transudative. The findings were then evaluated to determine the diagnostic value of each approach in identifying the effusion type and comparing them on the basis of sensitivity, specificity, positive predictive value and negative predictive value., Result: Pleural fluid cholesterol detected effusion as exudative with sensitivity of 91.94% and specificity of 80.00% against Light's criteria; with a sensitivity of 98.28% and specificity of 85.71% against the etiological diagnosis. Additionally, against the etiological diagnosis, sensitivity of both Light's and Heffner's criteria was 100%; however, specificity was 71.43% and 64.29% respectively, which is far less than that of pleural fluid cholesterol (85.71%). Furthermore, pleural fluid cholesterol was also found to have better results than protein ratio, LDH ratio and pleural fluid protein ratio in determining the type of effusion., Conclusion: When considering the avoidance of confusing outcomes in equivocal instances and cost effectiveness in developing nations, pleural fluid cholesterol can be one of the most useful alternative diagnostic methods for differentiating between exudative or transudative effusions., Competing Interests: The authors report no conflicts of interest., (© 2022 The Authors.)

BACKGROUND: Definite diagnosis of transudative or exudative pleural fluids often presents a diagnostic dilemma. The aim of this study was to evaluate whether amino-terminal brain natriuretic peptide (NT-proBNP) levels in pleural fluid has a diagnostic value for discriminating heart-failure related pleural effusions from non-heart-failure effusions. METHODS: Sixty-six subjects (40 male, mean age 61 ± 18 y) with pleural effusions were included. Samples of pleural fluid and serum were obtained simultaneously from each subject. Biochemical analysis, bacterial and fungal culture, acid-fast bacilli smear and culture, and cytology were performed on the pleural fluid. RESULTS: Subjects with heart-failure-related pleural effusion had significantly higher pleural NT-proBNP levels than other subjects (P < .001). Pleural and serum NT-proBNP measures were closely correlated (r = 0.90, P < .001). An NT-proBNP cutoff value of ≥ 2,300 pg/mL in pleural fluid had a sensitivity of 70.8%, a specificity of 97.6%, and positive and negative predictive values of 94.4% and 85.4%, respectively, for discriminating transudates caused by heart failure from exudates. Eight heart-failure subjects were misclassified as exudates by Light's criteria, 5 of whom received diuretics before thoracentesis. All misclassified subjects had pleural NT-proBNP levels higher than 1,165 pg/mL, which predicted heart-failure-associated transudates with 95.8% sensitivity and 85.7% specificity. CONCLUSIONS: Pleural fluid NT-proBNP measurement in the routine diagnostic panel may be useful in differentiation of heart-failure-related pleural effusions and exudative pleural fluids with reasonable accuracy, especially in heart-failure patients treated with diuretics. [ABSTRACT FROM AUTHOR]

Objective: Light's criteria, which were accepted in 1972 for the differential diagnosis of pleural effusions as transudates or exudates, are widely used worldwide. It has been reported in various studies that Light's criteria have lower specificity, and new recommendations have emerged. The discriminative ability of Light's criteria and adapted formulas, which are our new proposal, were studied by Receiver Operating Characteristics (ROCs) analysis and Area Under the Curves (AUCs). Material and Method: These criteria were evaluated in 451 patients in our study. Of these cases, 151 had transudates, while 300 patients presented with exudates. Results: AUCs of Light's criteria (P/Sprot, P/SLDH, PLDH) were measured as 0.931 (95%CI: 0.899-0.963), 0.936(95%CI: 0.904- 0967) and 0.957(95%CI: 0.934-0.981), respectively, and the differences between the measured values were found to be statistically significant (p<.001). AUCs of our new adapted formulas (F-1, F-2, F-3) were found to be slightly higher than those of Light's criteria, with the values of 0.987(95%CI: 0.976- 0.998), 0.935(95%CI 0:.908-0.963) and 0.980(95%CI: 0.966- 0.993), respectively, and the differences were also significant (p<.001). Conclusion: In our opinion, further studies are needed with a wider study population to determine the value of the new formulas in differentiating exudative and transudative pleural effusions. Proving our proposal would be useful in clinical practices. [ABSTRACT FROM AUTHOR]

Fifty years from their initial description, Light's criteria are still unhesitatingly accepted as the default reference test for separating pleural transudates and exudates. Efforts should be focused not so much on trying to find an even more reliable technique for categorizing PEs but on improving the misclassification rate of transudates that characterize Light's criteria. Despite their shortcomings, Light's criteria may well continue their reign for another 50 years. Long live the Light's criteria!, Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Abstract: Objectives: Assess whether age influences standard biochemical parameters used in the differential diagnosis of transudative and exudative pleural effusions. Design and methods: We retrospectively analyzed data from the database of our clinic from 225 patients with pleural effusions categorized based on their final diagnosis in 5 groups: transudates 41 (18%), uncomplicated parapneumonic 26 (12%), complicated parapneumonic 20 (9%), tuberculosis 35 (15%) and lung cancer 103 (46%). We tested whether age correlated with pleural fluid protein or lactate dehydrogenase. Results: There was a statistically significant inverse correlation only between the age and the pleural fluid protein content in patients with uncomplicated parapneumonic effusions with correlation coefficient r =−0.6 [(95% CI=−0.8 to −0.28); p =0.001]. Linear regression analysis showed that this association is given by the equation: age=101.998−10.03 protein. In the same group of patients age was not correlated with serum protein content. Conclusions: Our study shows that age may be a confounding factor in the differential diagnosis of transudative and exudative pleural effusions. Clinicians should be aware of this finding especially when dealing with elders. [Copyright &y& Elsevier]

Introduction: Light's criteria for pleural fluid analysis has long been the standard for distinguishing transudates from exudates. In pleural tuberculosis, the resulting pleural fluids are usually exudates. We present a case of presumed transudative effusion which was eventually diagnosed as pleural tuberculosis. Case description: A 59-year-old man with end-stage renal failure (ESRF) on regular haemodialysis presented with a one-day history of acute onset dyspnoea associated with pleuritic chest pain and cough. Chest radiograph revealed bilateral pleural effusions and thoracentesis was done. The pleural fluid result was interpreted as transudative effusion according to Light's criteria because his pleural fluid to serum protein ratio was less than 0.5. AFB 1+ was seen in the pleural fluid with negative gram stain and culture. This resulted in conflicting opinions on whether to start this patient on anti-tuberculous therapy (ATT) and there was even a suggestion to get a second opinion for the possibility of AFB fluid contamination. The initial diagnosis was written as fluid overload secondary to ESRF but ATT was started anyway to cover for pleural TB. On further analysis of his pleural fluid, the pleural protein 32 g/L which on its own is a marker of exudative effusion. Subsequent investigations revealed the presence of exudative ascitic fluid which further raised the suspicion for a concomitant peritoneal TB. Conclusion: Premature conclusion that the pleural fluid was transudative occurred probably due to the bilateral nature of the pleural effusion associated with a known tendency for the patient to develop pulmonary overload secondary to his ESRF. This case is a reminder that Light's criteria also requires serum and fluid LDH measurement for the diagnosis of transudative pleural effusion. More importantly, a high level of suspicion for TB is important when evaluating patients from areas where TB is prevalent and a positive AFB result should not be taken lightly. [ABSTRACT FROM AUTHOR]

Objective: Pleural effusions are common in pediatrics. When the etiology of a pleural effusion remains unknown, adult literature recommends the use of Light's criteria to differentiate a transudate from an exudate. Pediatricians may rely on adult literature for the diagnostic management of pleural effusions as Light's criteria has not been validated in children. The purpose of this study was to review the use of Light's criteria in hospitalized children with a pleural effusion of unknown etiology., Methods: Retrospective review was performed on children hospitalized with a pleural effusion requiring chest tube placement or thoracentesis between January 1, 2016 to January 1, 2017 at Children's Hospital Colorado. Charts were reviewed for primary team, use of Light's criteria, pleural effusion diagnosis, and 30-day recurrence of repeat intervention or fluid analysis., Results: Sixty-eight patients were hospitalized with a pleural effusion of unknown etiology requiring intervention. Only 16 pleural effusions (24%) were classified using Light's criteria. In those patients for whom Light's criteria was used, a diagnosis or change in management occurred in 10 of 16 patients (63%). Pleural effusions were most common on the cardiology service (26/68). Use of Light's criteria was most frequent on the oncology service (7/8). Thirty-day need for repeat intervention was lower in those with Light's criteria (13%) compared to those without (27%)., Conclusions: Light's criteria were utilized infrequently in hospitalized children with a pleural effusion of unknown etiology at a single institution. There was considerable practice variation among provider teams. When utilized, Light's criteria assisted in making a diagnosis or changing management in many patients, and may lead to a reduction in 30-day recurrence requiring repeat intervention., (© 2018 Wiley Periodicals, Inc.)