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Intakes of excess Na and insufficient K are two major contributors of heart diseases and stroke development. However, no precise study has previously been carried out on Na and K intakes among Indonesian adults. The present study aimed to estimate the Na and K intakes using two consecutive 24-h urine collections. Participants were community-dwelling adults aged between 20 and 96 years, randomly selected from a pool of resident registration numbers. Of the 506 participants, 479 (240 men and 239 women) completed urine collections. The mean Na excretion was 102·8 and 100·6 mmol/d, while the mean K excretion was 25·0 and 23·4 mmol/d for men and women, respectively. Na and K excretions were higher in participants with a higher BMI. A higher K excretion was associated only with younger age. More than 80 % of the participants consumed more than 5 g/d of salt (the upper limit recommended by the Indonesian government), whereas none of them consumed more than 3510 mg/d of K (the lower limit). The high Na and low K intakes, especially high Na among participants with high BMI, should be considered when future intervention programmes are planned in this country.

This cross-sectional study was undertaken to compare 24-h urine protein estimation with spot urine protein-creatinine ratio (PCR). 72 patients having proteinuria of > 150 mg/day were included in this study. 24-h urine total protein (UTP) test were also asked to give their mid-morning spot urine sample the following day for urine protein-creatinine ratio. The subjects were grouped according to their UTP into Groups as described follows: Group A 3.5 g/day. Pearson’s correlation (r) and paired Student’s T test were done. The paired T test showed no difference in the UTP and PCR in the subgroup having qualitative protein of zero and in group A. There was no agreement between the two methods used for quantitation. In the overtly proteinuric patients, the correlation between the UTP and PCR was positive in group A which was statistically significant (p = 0.05) whereas it was not significant (p = 0.07) in group B. Though there was a negative correlation in the massive proteinuria group C it was not significant (p = 0.65). Our study demonstrates that spot PCR can be reliable parameter for initial diagnostic criterion of proteinuria but for follow-up measurements and for proteinuria > 0.5 gm/day, 24-h UTP is the single most accurate measurement of protein excretion.

Kidney disease is a global public health problem, affecting over 750 million people worldwide. Glomerular Filtration Rate(GFR), which is calculated by measuring the creatinine clearance with 24-hour urine collection (CC) can be inaccurate due toimproper urine collection, causing the need for an easier and accurate method of calculation. This study was anobservational analytical cross-sectional research using consecutive retrospective sampling. Samples were data of patientswith Chronic Kidney Disease (CKD) who underwent CC test at the Clinical Pathology Laboratory of the Dr. Soetomo HospitalSurabaya during September-October 2018. Data were compared with the results of Cockcroft-Gault (CG), MDRD, andCKD-Epi formula, and were analyzed using the one-sample Kolmogorov-Smirnov test, paired T-test, and Wilcoxon SignedRank test. Correlation of CC results with CG, MDRD, and CKD-Epi results was tested with Spearman's rho and Bland Altmantest. The difference test of CC with CG, MDRD, and CKD-Epi showed results of (p=0.000), (p=0.194), and (p=0.468),respectively. There were significant differences between CC compared to CG, but not MDRD and CKD-Epi. There was amoderate correlation between CG, MDRD, CKD-Epi, and CC with r=0.529; 0.448, and 0.463, respectively. The mostcompatible formula was CKD-Epi. The measurement of GFR with CC correlated with CG, MDRD, and CKD-Epi; therefore, theycould be used as an alternative method to calculate GFR. Further experiments using an exogenous marker should beperformed to determine a suitable eGFR formula according to the degree of damage to the kidney.

Objectives To determine if alternative alkalinizing agents lead to similar changes in 24-hour urine pH and citrate compared to potassium citrate (KCIT). Many stone formers cannot tolerate KCIT due to side effects or cost. In these patients, we have prescribed potassium bicarbonate or sodium bicarbonate as alternative alkali (AA), though their efficacy is unclear. Methods We performed a retrospective cohort study of adult stone formers seen from 2000 to 2018 with 24-hour urine analyses. Two analyses were performed. The first evaluated the alkalinizing and citraturic effects in patients with baseline low urine pH or hypocitraturia off of any alkalinizing medications, who were subsequently treated with either KCIT or AA. The second analysis compared the pH and citrate in patients changing from KCIT to an AA. Reasons for switching were abstracted by chart review and cost savings percentages were calculated using GoodRx medication prices. Results When starting alkali therapy, the median increase in pH from baseline was 0.64 for KCIT and 0.51 for AA (P = .077), and the median increase in citrate from baseline was 231 mg for KCIT and 171 mg for AA (P = .109). When switching alkali therapy, median pH and citrate did not significantly change. Hyperkalemia (24%), GI upset (19%), and cost (17%) were the most common reasons cited for switching to an AA. AA represented a savings of 86%-92% compared to KCIT. Conclusion Alternative alkali appear to offer comparable improvements in 24-hour urine parameters and significant cost-savings compared to KCIT.

OBJECTIVE A 24-hour urine nor/metanephrine (urine NM-MN) measurements are a recommended first step in pheochromocytoma diagnosis. We hypothesized the presence of renal impairment (CKD) significantly confounds the results obtained in a urine NM-MN collection, giving artificially lower measurements. DESIGN Retrospective review of a comprehensive laboratory database with all urine NM-MN results from Southern Alberta from 2010 to 2018 (n = 15 505). After excluding high probability pheochromocytoma cases, results from patients with three levels of CKD (n = 796) were compared to those without CKD to determine the potential CKD effect. PATIENTS All patients having urine NM-MN collection during the time period, irrespective of ordering physician or test indication. MEASUREMENTS Urine NM-MN was measured by liquid chromatography-tandem mass spectrometry and glomerular filtration rate determined within a median of 1.9 days, as estimated by CKD-EPI equation. RESULTS In subjects with mild-to-moderate renal impairment, there was no continuous gradient between subnormal renal function and urine NM-MN measures. When the estimated GFR was

BACKGROUND There is little information available on quantitative description of the relationship between urine albumin-to-creatinine ratio (ACR) and 24-h urine protein excretion (24-h UPE). Here, we developed a calculation tool for 24-h UPE using the urine ACR and limited information on the request form. MATERIAL AND METHODS This was a retrospective and observational study. All individuals with same-day urine ACR and 24-h UPE tests in Sichuan Provincial People's Hospital from September 1, 2018 to December 31, 2019 were enrolled. Correlation and agreement between urine ACR and 24-h UPE were evaluated using correlation analysis and an intraclass correlation coefficient, respectively. The Durbin-Watson test and ANOVA were used to assess the performance of the calculation tool, and reliability of the prediction equation was evaluated in the validation group using residual error analysis. RESULTS A total of 906 participants were enrolled, including 639 participants in the development group and 267 in the validation group. Natural logarithm transformation was applied to remove skewness. Natural logarithm-transformed urine ACR correlated well with natural-logarithm-transformed 24-h UPE (Pearson coefficient=0.908; P0.001) and the agreement was consistently good (overall ICC=0.938; 95% CI: 0.928-0.947; P0.001). The multivariable regression model had good performance (R²=0.864) and high accuracy, demonstrated by results of residual error analysis. CONCLUSIONS We provide a practical calculation tool to estimate total protein excretion using urine ACR and readily accessible variables. However, 24-h UPE is still mandatory when proteinuria is over 10 g/day or when most proteinuria may not be of glomerular origin.

Background: Although 24-hour urine total protein (UTP) measurement is the gold standard method for detecting proteinuria in preeclamptic women, the procedure is lengthy and time consuming that might result in delay in diagnosis of the condition. This study aimed at deter­mining the correlation between these 2 parameters. Methods: This was a cross-sectional study done on 50 pregnant women with preeclamp­sia admitted at Bharatpur Hospital from September 2018 - January 2019. Patient with pre­eclampsia and having albumin ≥1 on urine dipstick, the sample was collected in every 12 hours interval on two separate well labeled container with the assistance of nursing staff. Total urine protein at 12-hour and 24-hour were measured by spectrophotometric method. The data were analyzed using SPSS version 21. Correlation between the 2 measurements was analyzed using Spearman’s rank correlation coefficient. p

Few population-based studies conducted in the Eastern Mediterranean region assessed salt intake by the measurement of 24-h sodium urine excretion (24-hUNa). The current study aimed to assess the trend of mean salt intake in Iranian adults between 1998 and 2013.These cross-sectional studies were performed on 564, 157, 509 and 837 randomly selected healthy adults aged18 years from Isfahan city, Iran, in 1998, 2001, 2007 and 2013, respectively. BP was measured using a mercury sphygmomanometer according to a standard protocol. Single 24-h urine was collected to assess 24-hUNa as a surrogate of salt intake, and 24-h urinary K (24-hUK). The estimated trend of salt intake was 9.5, 9.7, 9.6 and 10.2 g/day in total population (P 0.001). The increase in salt intake between 1998 and 2013 was significant only in men, (P 0.001). The risk of pre-hypertension was 21% and 18% significantly greater in the highest quartiles of UNa/UK after adjustment for potential confounders in 2001 and 2013, respectively, [OR (95% CI): 1.21 (1.03-1.64) and 1.18 (1.02-1.38), respectively].This population-based study indicated that mean salt intake was about two times of recommendation in Isfahan city, Iran, and suggest that it would be essential to implement a salt reduction strategy program in Iranian population. Longitudinal national studies with larger samples examining the trend of salt intake are warranted.

PURPOSE OF REVIEW Evaluation of the kidney stone patient includes measurement of 24 h urine chemistries. This review summarizes the application of physiologic principles to the interpretation of urine chemistries, using sulfate and ammonium to estimate diet acid load, and the renal response. RECENT FINDINGS There has been increased recognition of the need to measure urine ammonium excretion in the clinical setting in order to understand renal acid excretion. Some 24 h urine kidney stone panels include ammonium measurements, providing an opportunity to apply this measurement to clinical practice. In order to better interpret ammonium excretion, one needs an estimate of dietary acid load to understand the driving forces for ammonium excretion. Sulfate is also included in some kidney stone panels and functions as an estimate of diet acid load. Combining these analytes with urine pH, the clinician can quickly estimate dietary stone risk as well as potential bowel disease, acidification disorders, and the presence of urease producing bacteria; all of which can affect stone risk. SUMMARY Measurement of ammonium and sulfate excretion along with urine pH provide important insights into the acid/alkali content of diet, presence and severity of bowel disease, presence of renal acidification disorders, and urinary infection.

INTRODUCTION AND OBJECTIVE:To enable earlier preventative interventions or guide empiric therapy for kidney stone disease, our objective was to demonstrate feasibility of predicting 24-hour urine a...

INTRODUCTION AND OBJECTIVE:Recent studies show no benefit to a selective approach to preventive pharmacological therapy (PPT) for patients with urinary stone disease (i.e., obtaining 24-hour urine ...

In vitro experiments demonstrate calcium oxalate (CaOx) supersaturation (SS) drives CaOx nucleation and growth. We investigated the link between 24-hour urine SS CaOx and in vivo stone growth through a natural history, imaging study.Using an institutional review board-approved database, we sought80% CaOx stone formers who prior to stone intervention obtained 2 separate computerized tomography (CT) scans with at least one 24-hour urine collection between scans. Two blinded reviewers calculated bilateral 3-dimensional stone volume using the Visage 7® region of interest pen tool. CT volume difference was divided by time between scans, and SS CaOx was grouped into low (5), medium (5-10) and high risk (10). Statistical significance between groups was assessed by Kruskal-Wallis test.We identified 80 individuals with stone growth measured by 3-dimensional CT (mean ∼7 months between studies). Inter-reviewer reliability of CT volume measurement was well correlated (0.98, Gwet's AC2), and an arbitrator was only needed in 13/160 (8%) cases. Median stone volume growth/year was 15%, 71% and 177% for low, medium and high risk groups, respectively (p0.001). Despite inter-individual variation, best fit of mean SS CaOx vs stone volume growth was moderately correlated (Spearman's rho=0.53, p0.001).In a population of pure CaOx stone formers, increased 24-hour SS CaOx risk was associated with increased in vivo stone growth. Further investigations using CT volumetric stone growth may allow for the noninvasive study of stone growth modulators, improved stone risk prediction and development of a kidney stone simulator.

Hemodialysis adequately controls serum uric acid (UA) levels, making UA-lowering drugs unnecessary; scant data are available for peritoneal dialysis (PD). We analyzed blood, 24 h urine and dialysis fluid from twenty patients under PD, to assess UA levels and clearances, and factors associated with better performance and maintenance of target levels (

The purpose of this review paper is to describe the 24-h urine collection in terms of its utility, collection process, and common problems with its acquisition. Although 24-h urine collections are standard of care for high-risk stone formers, several nuances in test acquisition including inaccurate urine collections 50% of the time and poor patient compliance limit its potential utility. Compliance in obtaining 24-h urine collections has been shown to be improved in patients who have not undergone surgical treatment of urinary calculi, patients with metabolic stone disease or family history of stone disease, Caucasian ethnicity, and in those with more sedentary occupations. Studies show conflicting data of compliance regarding patient age and gender. Physicians must understand the difficulties regarding 24-h urine collections including patient compliance, variability between collections, and complexities with interpretation to best utilize this tool in guiding clinical management for the treatment of nephrolithiasis.

ispartof: KIDNEY INTERNATIONAL vol:98 issue:3 pages:782-784 ispartof: location:United States status: published

Background The 24-h urinary output of 5-hydroxyindoleacetic acid (5-HIAA) is used to monitor disease progression and treatment responses of neuroendocrine neoplasms (NENs). Several conditions are required for 5-HIAA assay, involving urine collection/preservation and food/drug restrictions. Aim To evaluate the correlation between 5-HIAA concentration in a spot urine sample and the output in a 24-h urine collection, and whether spot urine specimens can replace 24-h collection. Methods Patients with NENs or symptoms suggestive of NENs were asked to provide a separate spot urine at the end of the 24-h urine collection for 5-HIAA assessment. The upper reference limit for 24-h urinary 5-HIAA was 40 µmol/24 h. 5-HIAA measurements in spot urine samples were corrected for variation in urine flow rate by expressing results as a ratio to creatinine concentration. Results We included 136 paired urinary samples for 5-HIAA assessment from 111 patients (100 NENs). The correlation between 5-HIAA values measured in 24-h and spot urines was r = +0.863 (P r = +0.840 (P P P Conclusions The ratio of 5-HIAA to creatinine in a spot urine could replace the measurement of 5-HIAA output in a 24-h urine collection, especially for follow-up of patients with known elevated 5-HIAA levels.

We aim to describe factors that are associated with kidney stones 20 mm or larger. This information would potentially guide research regarding factors of kidney stone growth. We retrospectively reviewed a patient cohort who underwent surgical treatment for kidney stones. Patients with detailed demographics, 24-h urine testing, and kidney stone profiling were included. Large stone was defined as measuring 20 mm or more. Univariate analysis was conducted to assess variables associated with kidney stones larger than 20 mm. Multivariate logistic regression and statistical machine learning methods were used to infer prediction models. The specific composition of kidney stones, laboratory testing results, and detailed demographics of 277 patients were included in our analysis. Multiple variables were significantly associated with large stones in univariate analysis. The final model that predicts large stone size includes several variables from different domains: hypertension (OR = 1.91; 95% CI 1.06, 3.43), older age (60+ vs 20–40) (OR = 2.46; 95% CI 1.07, 5.63), decreased calcium oxalate supersaturation (OR = 0.92; 95% CI 0.85, 0.99), and higher percentage of protein in stone composition (OR = 5.64; 95% CI 2.04, 15.58). This model yields a sensitivity 83% and specificity of 56%. Models using machine learning algorithms identified similar predictors, but the performance varies. Our model yielded good performance, and it could potentially be used as a clinical tool for predicting large stones and identifying factors affecting kidney stone growth. Similar analysis in other cohorts should be pursued to externally validate findings.

24-h urine free cortisol (UFC) is an indicator of integrated cortisol secretion and established screening tool for Cushing's syndrome (CS). Doubts have been raised regarding specificity of immunoassays, and mass spectrometric techniques have been proposed as an alternative. In the present study we compared diagnostic accuracy of UFC measured with LC-MS/MS vs. immunoassay in patient with CS and patients where CS has been excluded. We examined 24-h urine samples from patients with surgically confirmed CS (n = 77; Cushing's disease (n = 44), ectopic CS (n = 5), adrenal CS (n = 28)) and patients in whom Cushing's syndrome was excluded (n = 97) by long-term follow up. UFC was first measured by automated chemiluminescence immunoassays (ADVIA Centaur, Siemens; LIAISON, DiaSorin). Aliquots of all samples were also analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Statistics: Passing-Bablok Regression, Receiver operating characteristic (ROC) analysis with Youden's index calculation. UFC of CS patients were higher with both immunoassays compared to LC-MS/MS (913 +/- 235 vs. 303 +/- 155 μg/24 h (ADVIA) and 898 +/-216 vs. 399 +/- 196 μg/24 h (LIAISON)). Similarly, UFC were higher with immunoassays than with LC-MS/MS in the control group (223 +/- 10 vs. 23 +/- 2 μg/24 h (ADVIA) and 105 +/- 6 vs. 27 +/- 4 ug/24 h for (LIAISON)). Passing-Bablok regression showed good correlation between LC-MS/MS and ADVIA as well as between LCMS/MS and LIAISON (r = 0.96 and r = 0.99, p 000.1) but less correlation in controls (r = 0.83 and r = 0.74, respectively, p 000.1). ROC calculation revealed the highest ROC AUC (0.89) for the LIAISON immunoassay, followed by LC-MS/MS (0.82) and the ADVIA (0.80). In direct comparison, AUCs from LC-MS/MS and immunoassays in the same patient were not statistically different (p 0,001). Best cut-off concentration to identify patients with CS was 234 μg/24 h (LIAISON), 51 μg/24 h for LC-MS/MS and 330 μg/24 h (ADVIA Centaur). In summary, UFC values were measured substantially higher by both immunoassays compared to LC-MS/MS. This is most likely due to cross-reactivity from interfering glucocorticoid metabolites. Nevertheless, all three methods correlated well. ROC analysis revealed the highest AUC for one of the immunoassays, although differences between the three methods were not significant. Direct comparison with LC-MS/MS indicates that high diagnostic accuracy can be obtained with suitable immunoassays.

Aims We investigated the dose–response association of 24-hour urine sodium and potassium with 24-hour ambulatory blood pressure. Design Cross-sectional community-based study. Methods Among the 1128 participants in the community-based cross-sectional survey, 740 participants (aged 20–70 years) with complete 24-hour urine collection and valid 24-hour ambulatory blood pressure monitoring were included in the study. Participants were grouped into younger (Results In the older population, nighttime blood pressure linearly increased with 24-hour urine sodium and the sodium to potassium ratio. For 24-hour urine sodium, adjusted β was 0.171 (95% confidence interval (CI) 0.036–0.305) for nighttime systolic blood pressure and 0.144 (95% CI 0.012–0.276) for nighttime diastolic blood pressure. For the 24-hour urine sodium to potassium ratio, adjusted β was 0.142 (95% CI 0.013–0.270) for nighttime systolic blood pressure and 0.144 (95% CI 0.018–0.270) for nighttime diastolic blood pressure. The 24-hour blood pressure linearly increased with the 24-hour urine sodium to potassium ratio and adjusted β was 0.133 (95% CI 0.003–0.262) for 24-hour systolic blood pressure and 0.123 (95% CI 0.003–0.244) for 24-hour diastolic blood pressure. Daytime blood pressure and 24-hour systolic blood pressure showed a significant but non-linear association with 24-hour urine sodium among the older population. In the younger population, 24-hour urine sodium, potassium and the sodium to potassium ratio were not associated with ambulatory blood pressure. Conclusion In the older population, 24-hour urine sodium and the sodium to potassium ratio showed a linear and positive association with nighttime blood pressure, and 24-hour urine sodium was associated with 24-hour systolic blood pressure and daytime blood pressure in a non-linear fashion.

Background: Nephrolithiasis is a worldwide health problem. Objectives This study investigated the frequency of urinary and serum metabolic abnormalities and their association with demographic characteristics in patients with nephrolithiasis. Methods: In this cross-sectional study, we assessed 376 patients with nephrolithiasis who referred to Motahari Medical Center, Shiraz from March 2017 to June 2017. Patients’ history, 24-hour urine analysis (for volume, calcium, uric acid, sodium, citrate, phosphate, and oxalate), and serum tests (for calcium, uric acid, and parathyroid hormone) were recorded in a data gathering sheet. P value < 0.05 was considered statistically significant. Results: The most common abnormality was a low volume of 24-hour urine (< 2000 mL), (73.7%), followed by hypercalciuria (23.9%), and hyperoxaluria (19.4%). Low 24-hour urine volume was more frequent in women (80.0% vs. 64.3%, P < 0.001), while hypercalciuria (37.0% vs. 18.3%, P < 0.001), and hyperphosphaturia (6.0% vs. 1.7%, P = 0.03) were more frequent in men. Moreover, hypercalciuria was more frequent in outdoor workers (39.7% vs. 21.1%, P = 0.003), whereas low urine volume was more frequent in indoor workers (79.0% vs. 61.1%, P = 0.006). Metabolic abnormalities were not different in terms of patients’ family history. Conclusions: Multiple factors affect the frequency and type of nephrolithiasis. Since these parameters are also influenced by race, culture, and dietary habits; thus each region must determine its own demographic features of renal stone. Based on our results, women had lower urine volume and higher urine citrate than men. Moreover, water intake is one of the most important factors that correlate with renal stone formation.

Introduction:Compliance with 24-hour urine collections for assessing kidney stone risk is important in assigning preventive therapy. We determined factors associated with compliance and the...

Introduction: Hypertensive disorder in pregnancy (HDP) is one of the most common medical complications affecting approximately 5-10% of pregnancies. It remains a major cause of maternal/perinatal mortality and morbidity. Proteinuria is a sign of preeclampsia where there is >300 mg of protein in 24 hour urine collection. This usually correlates with 30mg/dl or 1+ reading in a random urine specimen. The main objective of this study is to find out whether urine dipstick correlates with 24 hour urine protein. Methodology: This is a hospital based comparative study, where proteinuria by dipstick method was compared with 24 hour urinary protein in 60 cases of pre eclampsia at Paropakar Maternity and Women’s Hospital, Thapathali, Kathmandu. Results: The dipstick method of detecting proteinuria significantly correlated with the total 24 hour urine protein excretion by Esbach Albuminometer. A dipstick factor of ≥300mg/24 hour indicates proteinuria with sensitivity of 97.5%, specificity of 65%, positive predictive value of 84.78% and negative predictive value of 92.85%. 3+ value in dipstick had high significance with 24 hour urine protein by Esbach’s Albuminometer (R=0.983 ). The cost of dipstick was Nepalies Rs (NPR) 14 in comparison to 24 hour dipstick which cost NPR 80.Time needed to get report was immediate in case of dipstick but takes 48-50 hour in case of 24 hour urine protein. Conclusion: Timely collection of six hourly urine for detection of proteinuria by dipstick is comparable to 24 hour urinary protein determination in laboratory by Esbach Albuminometer, which is more time consuming and expensive.

The objective of this study was to determine the level of agreement between 3-day food records obtained as part of clinical care with 24-hour urine collections specifically assessing sodium, potassium, phosphorus, calcium, protein, and fluid intake.Data were collected from patients at a nephrology clinic in a metropolitan, academic medical center. Patients who completed both a 3-day food record and a 24-hour urine collection were analyzed. Food record and urine collection measurements were compared using a simple ratio, Pearson's correlation, and general linear models.Patients (n = 85) were 47.9 ± 15.2 years of age, 54% were female, with a mean serum creatinine of 1.3 ± 0.7 mg/dL and estimated glomerular filtration rate of 64.2 ± 25.6 mL/min. Patients had autosomal-dominant polycystic kidney disease (48.2%), nephrolithiasis (31.1%), chronic kidney disease (4.7%), or other genetic or cystic conditions impacting the kidney (12.9%). Nutrient intake was measured utilizing a 3-day food record. Food records and urine collections were compared using the values, correlations, and general linear models. Fluid intake demonstrated the highest agreement (ratio 1.01) and calcium demonstrated the least agreement (ratio 6.30). Significant correlations were demonstrated for phosphorus (r = 0.321, P = .003), magnesium (r = 0.256, P = .018), protein (r = 0.555, P .000), and fluid (r = 0.277, P = .010) intake. Food record intake of potassium (P = .046), protein (P = .004), and fluid (P = .010) were significant predictors of 24-hour urine excretion.3-day food records are useful tools to determine patient dietary patterns, but should be used with caution when assessing specific nutrient intake in clinical settings.

Background: Stone prevention is dependent on high fluid intake, with evidence that low urine volume (LUV) can promote nephrolithiasis in the absence of other metabolic abnormalities. Herein, we inv...

Many urinary biomarkers are adjusted for dilution using creatinine or specific gravity. The aim was to evaluate the variability of creatinine excretion, in 24 h and spot samples, and to describe an openly available variability biobank. Urine and blood samples were collected from 60 healthy non-smoking adults, 29 men and 31 women. All urine was collected at six time points during two 24 h periods. Blood samples were also collected twice and stored frozen. Analyses of creatinine in urine was performed in fresh urine using an enzymatic method. For creatinine in urine, the intra-class correlation (ICC) was calculated for 24 h urine and spot samples. Diurnal variability was examined, as well as association with urinary flow rate. The creatinine excretion rate was lowest in overnight samples and relatively constant in the other five samples. The creatinine excretion rate in each individual was positively correlated with urinary flow rate. The creatinine concentration was highest in the overnight sample and at 09:30. For 24 h samples the ICC was 0.64, for overnight samples it was 0.5, and for all spot samples, it was much lower. The ICC for urinary creatinine depends on the time of day of sampling. Frozen samples from this variability biobank are open for researchers examining normal variability of their favorite biomarker(s).

Background: There are multiple stone types, with each forming under different urinary conditions. We compared clinical and metabolic findings in pure stone formers (SFs) to understand whether there...

Background/objectives Isothiocyanate (ITC) is formed via the hydrolysis of glucosinolates by myrosinase, found in cruciferous vegetables. Although myrosinase is inactivated by the cooking process, no studies have incorporated the effect of cooking into the estimation of dietary ITC intake or evaluated the validity. We evaluated the validity of dietary ITC intake estimated from a food frequency questionnaire (FFQ), and urinary ITC levels using 24 h urine samples or a WFR (weighed food record), and evaluated the reproducibility of dietary ITC in two FFQs administered at an interval of 1-year. Subjects/methods The JPHC-NEXT Protocol Area included a total of 255 middle-aged participants across Japan. We calculated dietary ITC intake from WFR and two FFQs by assuming that cooked cruciferous vegetables contain zero ITC. Urinary ITC excretion was measured at two points during summer and winter. The validity and reproducibility of dietary ITC intake estimated by FFQ were assessed using Spearman's correlation coefficients. Results Although we observed a moderate correlation between dietary ITC intake derived from a 12-day WFR and urinary ITC excretion, notwithstanding the cooking process, the correlation between dietary ITC intake estimated by FFQ and mean urinary ITC excretion was low. However, the correlation was improved when we compared urinary ITC excretion and a 3-day WFR or FFQ collected during winter. Our FFQ showed good reproducibility. Conclusion Although seasonality is a critical factor, dietary ITC intake estimated using an FFQ showed moderate validity and reproducibility and can be used in future epidemiological studies.

Background and aims: The WHO Global Action Plan for the Prevention of non-communicable diseases (NCDs) recommends a 30% relative reduction in mean population salt/sodium intake. The study assessed the trend in the habitual salt intake of the Italian adult population from 2008 to 2012 to 2018–2019 based on 24-h urinary sodium excretion, in the framework of the CUORE Project/MINISAL-GIRCSI/MENO SALE PIU’ SALUTE national surveys. Methods and results: Data were from cross-sectional surveys of randomly selected age and sex–stratified samples of resident persons aged 35–74 years in 10 (out of 20) Italian Regions distributed in North, Centre and South of the Country. Urinary sodium and creatinine measurements were carried out in a central laboratory. The analyses included 942 men and 916 women examined in 2008–2012, and 967 men and 1010 women examined in 2018–2019. The age-standardized mean daily population salt (sodium chloride) intake was 10.8 g (95% CI 10.5–11.1) in men and 8.3 g (8.1–8.5) in women in 2008–2012 and respectively 9.5 g (9.3–9.8) and 7.2 g (7.0–7.4) in 2018–2019. A statistically significant (p

Introduction: The intraindividual variability in urinary creatinine excretion is notoriously large. The aims of this study were to investigate the variability of duplicate consecutive 24-hour urinary creatinine excretions in patients and to develop a model for the detection and correction of discrepant creatinine excretions. Materials and methods: A group of 270 patients (82 men and 188 women) were included in the study. We collected the following data: urinary 24-hour volumes (volumetric/gravimetric) and urinary creatinine concentrations (Jaffé/enzymatic) on both collection days. We performed specific calculations to detect discrepant creatinine excretions. Results: In 60 patients (22%) discrepant collections were found. Among the remaining 78%, 22% of the patients collected very accurately (almost identical urinary creatinine excretions). In this subgroup the volume ratios and the creatinine concentration ratios behave inversely as in a dilution curve. A theoretical model and six collection scenarios were developed to detect, interpret and correct discrepant collections. Practical examples are given to illustrate the use of the model in successful correction of creatinine and other analytes for under- or overcollection. Conclusions: We conclude that missed or overcollected urine volumes are the largest source of variation in creatinine excretion. Discrepancies in consecutive duplicate 24-hour creatinine excretions can be detected and corrected with specific calculations by means of the presented model. The effectiveness of these corrections is demonstrated with examples from daily practice. These calculations can be easily automated.

Metabolic factors underlying the recent increase in stone prevalence over the past decades are not well understood. Herein, we evaluate temporal, geographic and gender-specific trends in metabolic risk factors in recurrent kidney stone formers.A systematic literature review of metabolic risk factors for stone formation was conducted, inclusive of the last four decades. Studies with inadequate 24 h urine metabolic data, pediatric or those with less than 50 patients were excluded. The primary outcome was prevalence of each metabolic risk factor, compared between studies published prior to the year 2000 vs those following. Geographic and gender differences were secondary outcomes.Twenty-eight articles met inclusion criteria, of which 10 (Prevalence of metabolic risk factors for nephrolithiasis significantly increased in recent years. These findings are hypothesis-generating and may provide valuable insight into the epidemiology, prevention and management of recurrent stone disease. Dietary modifications and innovative medical therapies are needed to decrease metabolic risk factors underlying nephrolithiasis.

Sodium intake and compliance with dietary sodium modification are typically assessed using a 24-h urine collection analyzed using flame photometry, but this is inconvenient. Spot urine samples have been investigated as alternatives to 24-h collections, but their accuracy is poor. Since sodium and chloride are present in equal concentrations in dietary salt, chloride test strips may provide a suitable proxy for at-home measurement of urine sodium concentrations. We aimed to determine whether (i) chloride test strips provide a reliable measure of urinary sodium compared to the gold standard flame photometry and (ii) multiple spot samples accurately reflect 24-h urine sodium. We recruited 43 participants (19 males) aged 23.6 ± 0.6 years to complete multiple consecutive spot samples (morning and evening) along with a 24-h urine sodium collection. Urine 24-h sodium estimates using chloride test strips (114.6 ± 7.5 mmol/day) were highly correlated (r = 0.900, p 0.0001) with flame photometry (121.1 ± 7.7 mmol/day) with a bias of -6.53 ± 22.2 mmol/day. Use of a three-spot sample average (both morning and evening spot samples) with a correction factor applied (122.9 ± 4.1 mmol/day) provided a good approximation of 24-h sodium measured by flame photometry (125.6 ± 9.0 mmol/day), with a bias of -2.55 ± 43.9 mmol/day. Chloride test strips applied to a 24-h urine collection provide a highly accurate measure of urinary sodium excretion, permitting convenient at-home sample collection and analysis. Their application to multiple spot samples provides a reasonable approximation of sodium excretion that can be used to conveniently monitor attempts at dietary sodium manipulation, without the inconvenience of completing a 24-h urine sample.

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Background Little is known about the capacity of overnight and spot urine samples to estimate changes in mean salt intake over time. The objective of this review was to compare the estimates of change in mean population salt intake based on 24-h urine and overnight/spot urine samples. Methods Studies were systematically identified through searches of peer-reviewed databases (Medline, Embase, Global Health, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews) and grey literature. Studies that reported estimates of mean salt intake for at least two time points based on both 24-h and overnight/spot urines were deemed eligible. The capacity of overnight/spot urine samples to estimate the change in mean salt intake was assessed both at the individual-study level and overall through random-effects meta-analyses. The level of heterogeneity was assessed through the I2 statistic. Subgroup and sensitivity analyses were conducted to explore possible sources of heterogeneity, and check the robustness of the findings from the primary analysis. Results A total of 1244 records were identified, 50 were assessed as full text, and 14 studies met the criteria, capturing data on 7291 participants from seven countries. Nine and five studies collected overnight and spot urines, respectively. The comparison of the change in mean salt intake between 24-h and overnight/spot urines showed some inconsistencies at the individual study-level. The pooled mean change in salt intake was − 0.43 g/day (95% CI − 1.16 to 0.30; I2 = 95%) using 24-h urines, and − 0.22 g/day (− 0.65 to 0.20; I2 = 87%) using overnight/spot urines, with a pooled difference-in-differences between the two methods of 0.27 g/day (− 0.23 to 0.77; I2 = 89%). Subgroup analyses showed substantial heterogeneity for most subgroups. Sensitivity analyses did not change the effect observed in the primary analysis. Conclusion The evidence for the capacity of overnight/spot urines to estimate changes in mean salt intake over time is uncertain. More research where overnight/spot urines are collected in parallel with 24-h urines is needed to enable a more in-depth evaluation of these alternative approaches to estimating change in mean salt intake.

BackgroundThe study was designed to estimate daily salt intake, its discretionary use in healthy individuals and to validate three common methods for salt estimation in Pakistani population.MethodsInformation on demography and discretionary salt use was collected healthy adults (>18 years) along with a blood sample, spot urine sample and 24 hours urine samples. Sodium, chloride, potassium levels and serum creatinine were measured using standard methods. For daily salt estimation, three common methods i.e. INTERSALT, Tanaka and Kawasaki were validated for their applicability in local settings.ResultsOverall 24 h sodium excretion was 158 mmol/l indicating intake of 8.64 (±4.43) grams salt per day which was significantly associated with male gender (p. ConclusionDaily intake of salt was high than recommended by the WHO. Findings showed that none of the three methods could be used for estimating daily intake of salt in local settings of Pakistan.

PURPOSE The commonly used 24-hour collection technique has been the mainstay of diagnosis for supersaturation but has some certain limitations. Hence, superiority of multiple short urine collections as a new alternative in precipitation risk assessment was assessed compared to the standard 24-hour urine collection among healthy subjects. MATERIALS AND METHODS Individual urine samples of 26 healthy subjects were acquired every 2 to 3 hours throughout the 24 hours. Urine samples were obtained and the time and volume of each sample were recorded. Urinary constituents involved in precipitation including, sodium-potassium, chloride, calcium, phosphate, citrate, magnesium, urea, creatinine and pH were measured. A simulated 24-hour collection was recalculated by the totalling of all shorter urine collections volume and urinary constituents excretions throughout the day. RESULTS Urine pH, urine creatinine and precipitation rate had a significantly lower values in 24-hours urine collection compared to one individual value of multiple urine collections by -0.769 (P

Background and Aims All living kidney donors undergo assessment of renal function by evaluation of Glomerular Filtration Rate (GFR). 51Cr-EDTA is one of the most widely used marker for measuring GFR but it is hampered by cost and laboriousness as well as not being widely available in Malaysia. Measuring 24-hour urine for creatinine clearance (Ccr) is a common alternative when exogenous filtration markers are not available. Ccr suffers from over/underestimation of measured GFR (mGFR) due to errors in urine collection and tubular secretion of creatinine. This is a study to compare the correlation of Ccr against 51Cr-EDTA in measuring GFR among the living donors in Malaysian population. Method This is a cross-sectional, single-centre study of a cohort of living kidney donor candidates from January 2007 to March 2019. All candidates who had mGFR done with both 51Cr-EDTA and Ccr in University Malaya Medical Centre were enrolled. Special consideration was taken to account for adequate urine sampling for Ccr. Clinical data was analysed for correlation, bias, precision and accuracy between Ccr and 51Cr-EDTA. Results A total of 83 living kidney donors with a mean age of 45.60 ± 11.06 years and body mass index (BMI) of 24.36 ± 4.03 were enrolled. Female comprised 74.7% of the donors while Chinese, Malay and Indian accounted for 67.5%, 20.5% and 7.2% of the donors respectively. The study group had a mean serum creatinine of 63.37 ± 16.00 umol/L with a urine volume of 2.03 ± 0.81 L (range 0.70 – 3.82). mGFR from 51Cr-EDTA was 125.56 ± 27.64 ml/min/1.73m2 (range 77.0 – 194.3) whereas calculated Ccr was 136.05 ± 36.15 ml/min/1.73m2 (range 75.32 – 280.06). The correlation coefficient between Ccr and 51Cr-EDTA is moderate (r = 0.43) (p < 0.01). Mean absolute bias between Ccr and 51Cr-EDTA was 10.59 ± 37.99 ml/min/1.73m2 (p < 0.05). The accuracy of Ccr within 30% of 51Cr-EDTA was 77.11%. Conclusion Our study showed that Ccr significantly overestimates mGFR compared to 51Cr-EDTA. However, there is a significantly moderate positive correlation between Ccr and 51Cr-EDTA. Thus, in the absence of 51Cr-EDTA, Ccr is a clinically acceptable alternative if utilized with care and understanding its limitations.

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Background: Obesity, diabetes and hypertension are common in the general population, and do not discriminate between patients (pts) with or without Cushing’s syndrome (CS). Thus, Endocrine Society guidelines recommend biochemical testing in pts with multiple features compatible with the diagnosis (1). A 24-hour (d) urine cortisol (UF) is one of the recommended screening tests. However, tandem mass spectrometry (MS/MS) measurement of UF may be less sensitive than immunoassay because of antibody cross-reactivity with cortisol-like compounds. Cortisone (E), the product of 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) inactivation of cortisol, can be measured in the urine (UE) by MS/MS and might improve the sensitivity of UF alone. The goal of this study was to compare the diagnostic utility of UE, UF, their sum (UF+UE) and their ratio (rUF/UE) for the detection of CS. Methods: We retrospectively reviewed 35 pts evaluated for CS from 1/2017 to 9/2019. UF (reference range (RR), 3.5-45 ug/d) and UE (RR 17-129 ug/d) were measured by MS/MS. CS etiology was later confirmed in 24 pts by pathology and/or tumor localization [14 female; 14 Cushing’s disease, 7 ectopic ACTH secretion (EAS), 3 presumed EAS awaiting surgery; 46 UF and UEs], and was excluded (noCS) in 11 pts followed over time [8 female; 65 UF and UEs with salivary cortisol and/or dexamethasone suppression]. For CS patients with multiple results, the sample with the lowest UF was compared with all available samples from the NoCS group. Results: Using a single result for each CS pt, the median (range) for UF, UE, UF+UE and rUF/UE were 281 ug/d (34 - 32,444), 358 ug/d (171 - 802), 642 ug/d (232 - 33246) and 0.78 (0.13 - 40.5). By contrast, using all observations in noCS pts, median (range) for UF, UE, UF+UE and rUF/UE were 13.6 ug/d (2.2 - 88.8), 79.5 ug/d (4.9 - 253), 98.2 ug/d (7.1 - 342) and 0.2 (0.05-0.67). Using the upper RR (or their sum) as a criterion for abnormality, all CS pts had abnormal UE and UF+UE; 45/46 had abnormal UF. In noCS samples, abnormal values were seen in 12/65 UF (3 pts), 14/65 UE (4 pts), and 13/65 UF+UE (3 pts). The rUF/UE was < 0.70 in all noCS pts and in 9/24 CS patients. Within this group, the UF+UE was > 230 ug/d in two noCS patients (2/3 and 2/7 samples/pt), and in all 9 CS patients, including two with normal UF and two with UF 170 ug/d identified the same noCS and CS patients. Conclusion: UF remains an important tool for screening of CS. The addition of UE and UF+UE may provide additional information to discriminate CS from noCS in patients with rUF/UE < 0.70. In contrast to CS pts, noCS pt consistently had UF+UE > 230 ug/d or UE > 170/d, underscoring the importance of multiple samples. Additional study, especially of pts with mild hypercortisolism, is needed to determine optimal diagnostic criteria. 1.Nieman L et al. J Clin Endocrinol Metab 93:1526, 2008

The purpose of this study was to examine 24 h urinary hydration markers in non-Hispanic White (WH) and non-Hispanic Black (BL) males and females. Thirteen males (BL, n = 6, WH, n = 7) and nineteen females (BL, n = 16, WH, n = 3) (mean &plusmn, SD, age, 20 &plusmn, 4 y, height, 169.2 &plusmn, 12.2 cm, body mass, 71.3 &plusmn, 12.2 kg, body fat, 20.8 &plusmn, 9.7%) provided a 24 h urine sample across 7 (n = 13) or 3 (n = 19) consecutive days (148 d total) for assessment of urine volume (UVOL), urine osmolality (UOSM), urine specific gravity (USG), and urine color (UCOL). UVOL was significantly lower in BL (0.85 &plusmn, 0.43 L) compared to WH college students (2.03 &plusmn, 0.70 L) (p &lt, 0.001). Measures of UOSM, USG, and UCOL, were significantly greater in BL (716 &plusmn, 263 mOsm∙kg&minus, 1, 1.020 &plusmn, 0.007, and 4.2 &plusmn, 1.4, respectively) compared to WH college students (473 &plusmn, 194 mOsm∙kg&minus, 1, 1.013 &plusmn, 0.006, 3.0 &plusmn, 1.2, and respectively) (p &lt, 0.05). Differences in 24 h urinary hydration measures were not significantly different between males and females (p &gt, 0.05) or between the interaction of sex and race/ethnicity (p &gt, 0.05). Non-Hispanic Black men and women were inadequately hydrated compared to their non-Hispanic White counterparts. Our findings suggest that development of targeted strategies to improve habitual fluid intake and potentially overall health are needed.

OBJECTIVE To determine if obtaining a 24-hour urine collection (24HU) in stone formers is associated with decreased recurrent stone episodes. METHODS Using the MarketScan database, adults 17-62 years old with nephrolithiasis were identified between 2007 and 2017 with a minimum of 3-year follow up. High-risk stone formers, those undergoing stone surgery, and those with history of recurrent stones were identified. The exposure was a 24HU within 6 months of primary diagnosis. The outcome was recurrent stone episodes—defined by stone-related emergency room visits, hospitalizations, or stone surgery 90 days to 3 years after diagnosis. Logistic regression was used to estimate recurrence risk by 24HU exposure for the overall cohort and sub-cohorts limited to known recurrent stone formers, high-risk subjects, and those having stone surgery. RESULTS Of 434,055 subjects analyzed, 30,153 (6.9%) had a 24HU. An annual decline in 24HU utilization was seen (7.5%-5.8%). Regional variation in usage rate was also observed. On multivariate analysis, completing a 24HU was not associated with risk of recurrence in any of the following cohorts: recurrent stone formers (OR 0.98, 95% CI 0.9-1.07), both high risk and recurrent stone formers (OR 0.95 [0.8-1.13]), those undergoing surgery (OR 1.02 [0.97-1.07]); a positive association with 24HU and recurrence was seen in those labeled high-risk (OR 1.08 [1.01-1.16]) and in all-comers (OR 1.15 [1.12-1.19]). CONCLUSION The 24HU was not associated with decreased recurrence rates in the overall population nor in higher risk sub-cohorts.

Purpose The objective of this pilot study was to determine the frequency of urination and the concentration of four hazardous drugs (cyclophosphamide, ifosfamide, methotrexate, and fluorouracil) in workers’ 24-h urine samples in relation to exposure to traces with hazardous drugs. Methods The study was conducted in three healthcare centers in the region of Montréal, Quebec, Canada. We recruited healthcare workers (nurses and pharmacy technicians) assigned to the hematology-oncology department. Each participant was asked to collect all urine voided during a 24-h period, to fill out an activity journal documenting tasks performed and to document the use of personal protective equipment. Samples were analyzed for cyclophosphamide, ifosfamide, methotrexate, and alpha-fluoro-beta-alanine (FBAL, the main urinary metabolite of 5-fluorouracil). Drugs were quantified by ultra-performance liquid chromatography-tandem mass spectrometry (positive electrospray MRM mode). Results Eighteen healthcare workers (10 nurses and 8 technicians) were recruited and provided consent to participate. Urine samples were obtained between 1 September and 30 September 2019. The number of urinations over the 24-h collection period ranged from 3 to 11 per participant. A total of 128 urine samples were analyzed for the 18 workers. All urine samples were negative for the four antineoplastics tested. Conclusion No traces of cyclophosphamide, ifosfamide, methotrexate, or FBAL were found in the 24-h urine samples of 18 healthcare workers practicing in three healthcare facilities in Quebec. Although it was feasible to collect 24-h urine samples in this research project, it appears unrealistic to do so recurrently as part of a large-scale surveillance program.

Background Accurate assessments of sodium intake in children are important for the early prevention of cardiovascular disease. There is currently no accurate simple and feasible sodium intake approach for children. This study intends to validate the accuracy of 24‐hour urinary sodium excretion ( UN aV) estimation in children using 3 common formulas: the Kawasaki, INTERSALT (International Cooperative Study on Salt, Other Factors, and Blood Pressure), and Tanaka formulas. Methods and Results A hospital‐based child population in China was enrolled in the study and completed 24‐hour urine sample collection. Concentrations of sodium, potassium, and creatinine in 24‐hour urine and spot urine samples were measured. Mean difference as well as absolute and relative differences and misclassification between estimation and measurement of UN aV with 3 commonly used formulas were compared and analyzed. A total of 129 participants aged 5 to 16 years were eligible for analysis. Mean measured UN aV was 2694.9 mg/day. Mean differences between estimated and measured UN aV by the Kawasaki, INTERSALT , and Tanaka formulas were 2367.6, 26.4, and 258.8 mg/day, respectively. Proportions of relative differences of over 40% for the Kawasaki, INTERSALT , and Tanaka formulas were 79.8%, 34.9%, and 38.5%, respectively. Misclassification rates were 73.1% for Kawasaki, 69.0% for INTERSALT , and 62.4% for Tanaka at the individual level. Conclusions The results from our study do not support estimation of UN aV for children by the Kawasaki, INTERSALT , and Tanaka formulas using single spot urine samples because of the potential risk for misclassification at the individual level.

Objective:We assessed the validity of a recently developed dish composition database (DCD) against urinary biomarkers compared with a standard food composition database (FCD).Design:Intakes of protein, Na and K were estimated by 2 × 24 h urine collections and by 4 d dietary record data based on the DCD (including 128 dishes) or FCD (including 1878 foods).Setting:Japan.Participants:A total of 161 men and 163 women aged 20–69 years.Results:Compared with the 24 h urine-based estimates, the median intakes estimated using the DCD and FCD differed significantly for protein and Na in men and for Na and K in women. Deattenuated Spearman correlation coefficients using 24 h urine-based estimates for the intakes of protein, Na and K were lower in the DCD (respectively: 0·26, 0·15 and 0·44 in men; 0·22, 0·27 and 0·22 in women) than those in the FCD (respectively: 0·43, 0·40 and 0·59 in men; 0·33, 0·45 and 0·42 in women). When data on dish portion size reported by participants were used for estimation instead of standard portion-size data based on the DCD, the accuracy of the estimated median intakes did not change notably, whereas the deattenuated correlation coefficients improved (for protein, Na and K respectively: 0·32, 0·31 and 0·56 in men; 0·31, 0·41 and 0·39 in women).Conclusions:The DCD supported by individual-level information on dish portion size showed fair to moderate validity in ranking individuals according to their intakes of protein, Na and K, similar to the FCD.

Due to the difficulty of collecting 24-h urines in the stone-forming patient, some authors have suggested other types of urine collection, but their usefulness is not yet well studied. The objective of this study is to evaluate the variation of urinary supersaturation (SS) throughout the day and to analyze whether timed urine collections offer accurate information. 48 urine samples were collected from 12 young adults. Each 24-h urine was collected on 7 2-h urine fractions and a 10-h overnight sample. Solute concentrations and SS for calcium oxalate (CaOx), calcium phosphate (CaP), and uric acid (UA) were determined. Linear regression and relative importance of predictors were used to determine the percentage of R2 attributed to each timed collection (individual SS). 43 24-h urine samples were included in the study. The highest SS values were: for CaOx, night period and first morning urine; for CaP, between 2 and 6 pm and at night; for UA, between 8 am and 12 pm. For CaOx, the SS from the samples between 8 pm and 8 am accounted for more than 40% of the R2; for CaP, the results were more equally distributed throughout the day, and for UA, the SS values from 12 to 4 pm accounted for more than 45% of the observed variability. In conclusion, urinary SS varies throughout the day, being higher for CaOx and CaP at night, and in the early morning for UA. For CaOx and UA, the overnight and 12-4 pm urine samples, respectively, contribute most to the variability observed in the SS of 24-h urine.