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Analytical performance specifications (APS) represent the criteria that specify the quality required for laboratory test information to satisfy clinical needs. In 2014 the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) considered timely to update the topic of APS by organizing a conference in Milan in which some strategic concepts were proposed. Here I summarize the essential points representing the EFLM Strategic Conference heritage and discuss the approaches that will permit us to become more concrete, including roles and main actions expected from each of involved stakeholders for contributing a quantum leap forward in the way of practicality of Milan consensus about APS. [ABSTRACT FROM AUTHOR]

This document discusses the concept of analytical performance specifications (APS) in laboratory medicine. It provides an overview of previous conferences and consensus documents on setting APS, including the 2014 EFLM Strategic Conference. The 2023 CELME conference aimed to explore the three models from the Milan conference and offer practical recommendations for their application. The document emphasizes the importance of APS in ensuring harmonized medical laboratory results for patient care. It also discusses the challenges in determining measurement uncertainty and the need for education on APS usage. The document concludes by highlighting important questions for further consideration, such as the creation of a single database for APS and the intended use and aspirational nature of APS. [Extracted from the article]

To be accurate and equivalent among assays, laboratory results should be traceable to higher-order references and their quality should fulfill maximum allowable measurement uncertainty (MU) as defined to fit the intended clinical use. Accordingly, laboratory professionals should estimate and validate MU of performed tests using appropriate analytical performance specifications (APS). Current consensus supports the derivation of APS by using one of the three models established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Strategic Conference held in Milan in 2014. It is recognized that some models are better suited for certain measurands than for others and the attention should be primarily directed towards their biological and clinical characteristics. Among others, model 3 should reflect the state of the art of the measurements that can be defined as the best analytical performance that is technically achievable. Taking serum C-reactive protein and ferritin as examples, here we describe the theoretical premises and the experimental protocol to be used to derive APS for MU when a measurand is allocated to this model. Although the model lacks a direct relationship with clinical outcomes, useful information about the in vitro diagnostic medical device performance and the average quality of provided results may be obtained. [ABSTRACT FROM AUTHOR]

In addition to the correct implementation of calibration traceability, the definition and fulfillment of maximum allowable measurement uncertainty (MAU) are essential in assuring that laboratory measurements are clinically usable. Across the entire calibration hierarchy, three major contributors to the measurement uncertainty (MU) budget are identified, starting with the higher-order reference providers, extending through the in vitro diagnostic (IVD) manufacturers and their processes for assigning calibrator values, and ending with medical laboratories generating the random variability of results reported to clinicians. To understand if it is possible to achieve MAU and, consequently, to fix the possible drawbacks, the definition of combined MU budget limits across the entire calibration hierarchy has a central role. In particular, quality specifications for MU of reference and commercial calibrator materials should be defined according to the MAU on clinical samples. All involved stakeholders (i.e., higher-order reference providers, IVD manufacturers, medical laboratories) should be prepared to improve their performance whenever the clinical application of the test is made questionable by the failure to achieve MAU. [ABSTRACT FROM AUTHOR]

This document discusses the measurement uncertainty (MU) of total protein in urine (TPU) and its importance in evaluating the quality of laboratory results. The ISO Technical Specification 20914 provides guidance for estimating MU, but information about MU of TPU is lacking. The study applied this approach to four commercial measuring systems for TPU and found that the MU on clinical samples was consistent across the systems. However, there are challenges in defining the measurand and establishing metrological traceability. The study suggests that the performance of the evaluated systems could be used to establish analytical performance specifications for TPU. [Extracted from the article]

According to ISO 15189:2022, analytical performance specifications (APS) should relate to intended clinical use and impact on patient care. Therefore, we aimed to develop a web application for laboratory professionals to calculate APS based on a simulation of the impact of measurement uncertainty (MU) on the outcome using the chosen decision limits, agreement thresholds, and data of the population of interest. We developed the "APS Calculator" allowing users to upload and select data of concern, specify decision limits and agreement thresholds, and conduct simulations to determine APS for MU. The simulation involved categorizing original measurand concentrations, generating measured (simulated) results by introducing different degrees of MU, and recategorizing measured concentrations based on clinical decision limits and acceptable clinical misclassification rates. The agreements between original and simulated result categories were assessed, and values that met or exceeded user-specified agreement thresholds that set goals for the between-category agreement were considered acceptable. The application generates contour plots of agreement rates and corresponding MU values. We tested the application using National Health and Nutrition Examination Survey data, with decision limits from relevant guidelines. We determined APS for MU of six measurands (blood total hemoglobin, plasma fasting glucose, serum total and high-density lipoprotein cholesterol, triglycerides, and total folate) to demonstrate the potential of the application to generate APS. The developed data-driven web application offers a flexible tool for laboratory professionals to calculate APS for MU using their chosen decision limits and agreement thresholds, and the data of the population of interest. [ABSTRACT FROM AUTHOR]

Alanine aminotransferase (ALT) represents the first-level test to detect individuals with hepatocellular damage of any etiology. However, it has been highlighted that the lack of assay harmonization may lead to overdiagnosis and unnecessary further testing if guideline-recommended fixed cut-offs are uncritically employed. To solve the issue of ALT (dis)harmonization and improve the interpretation of its values, a series of urgent actions for documenting and validating metrological traceability of serum ALT measurements, as described in this paper, are no longer postponeable. It is time that all medical laboratory stakeholders (in vitro diagnostic manufacturers, laboratorians, external quality assessment scheme organizers) actively co-operate to implement the ALT standardization in a concerted action following well-established theoretical assumptions and applying experimental approaches described in literature. [ABSTRACT FROM AUTHOR]

Recently, Abbott Diagnostics marketed a new generation of Alinity enzyme assays, introducing a multiparametric calibrator [Consolidated Chemistry Calibrator (ConCC)] in place of or in addition to factor-based calibrations. For alkaline phosphatase (ALP), both calibration options are offered, i.e., with ConCC (ALP2) and with an experimental calibration factor (ALP2F). Both options are declared traceable to the 2011 IFCC reference measurement procedure (RMP). Before to replace the old generation (ALP1) with the new one, we decided to validate the trueness of ALP2/ALP2F. Three approaches were employed: (a) preliminary comparison on 48 native frozen serum samples with ALP1, of which traceability to RMP was previously successfully verified; (b) examination of three banked serum pools (BSP) with values assigned by RMP; (c) direct comparison with RMP on a set of 24 fresh serum samples. Bias estimation and regression studies were performed, and the standard measurement uncertainty associated with ALP measurements on clinical samples (uresult) was estimated and compared with established analytical performance specifications (APS). ConCC commutability was also assessed. A positive proportional bias was found with both ALP2 and ALP2F when compared to ALP1 and RMP. This positive bias was confirmed on BSP: in average, +13.1 % for ALP2 and +10.0 % for ALP2F, respectively. uresult were 13.28 % for ALP2 and 10.04 % for ALP2F, both not fulfilling the minimum APS of 4.0 %. Furthermore, ConCC was not commutable with clinical samples. Our results unearth problems in the correct implementation of traceability of Alinity ALP2/ALP2F, with the risk for the new assay to be unfit for clinical purposes. [ABSTRACT FROM AUTHOR]

Alanine aminotransferase (ALT) represents the first-level test to detect individuals with hepatocellular damage of any etiology. However, it has been highlighted that the lack of assay harmonization may lead to overdiagnosis and unnecessary further testing if guideline-recommended fixed cut-offs are uncritically employed. To solve the issue of ALT (dis)harmonization and improve the interpretation of its values, a series of urgent actions for documenting and validating metrological traceability of serum ALT measurements, as described in this paper, are no longer postponeable. It is time that all medical laboratory stakeholders (in vitro diagnostic manufacturers, laboratorians, external quality assessment scheme organizers) actively co-operate to implement the ALT standardization in a concerted action following well-established theoretical assumptions and applying experimental approaches described in literature. [ABSTRACT FROM AUTHOR]

Recently, Abbott Diagnostics marketed a new generation of Alinity enzyme assays, introducing a multiparametric calibrator [Consolidated Chemistry Calibrator (ConCC)] in place of or in addition to factor-based calibrations. For alkaline phosphatase (ALP), both calibration options are offered, i.e., with ConCC (ALP2) and with an experimental calibration factor (ALP2F). Both options are declared traceable to the 2011 IFCC reference measurement procedure (RMP). Before to replace the old generation (ALP1) with the new one, we decided to validate the trueness of ALP2/ALP2F. Three approaches were employed: (a) preliminary comparison on 48 native frozen serum samples with ALP1, of which traceability to RMP was previously successfully verified; (b) examination of three banked serum pools (BSP) with values assigned by RMP; (c) direct comparison with RMP on a set of 24 fresh serum samples. Bias estimation and regression studies were performed, and the standard measurement uncertainty associated with ALP measurements on clinical samples (uresult) was estimated and compared with established analytical performance specifications (APS). ConCC commutability was also assessed. A positive proportional bias was found with both ALP2 and ALP2F when compared to ALP1 and RMP. This positive bias was confirmed on BSP: in average, +13.1 % for ALP2 and +10.0 % for ALP2F, respectively. uresult were 13.28 % for ALP2 and 10.04 % for ALP2F, both not fulfilling the minimum APS of 4.0 %. Furthermore, ConCC was not commutable with clinical samples. Our results unearth problems in the correct implementation of traceability of Alinity ALP2/ALP2F, with the risk for the new assay to be unfit for clinical purposes. [ABSTRACT FROM AUTHOR]

Metabolic dysfunction-associated fatty liver disease (MAFLD) may progress to advanced liver fibrosis (ALF). We evaluated the diagnostic accuracy of a novel Liver Fibrosis Risk Index (LFRI) in MAFLD subjects using transient elastography (TE) as the reference method for liver fibrosis measurement and then the diagnostic performance of a new two-step non-invasive algorithm for the detection of ALF risk in MAFLD, using Fibrosis-4 (FIB-4) followed by LFRI and comparing it to the reference algorithm based on FIB-4 and TE. We conducted a prospective study on 104 MAFLD European adult subjects. All consenting subjects underwent TE and measurements of FIB-4 and LFRI. For FIB-4 and TE, validated cut-offs were used. An ROC analysis showed that LFRI diagnosed severe fibrosis with moderate accuracy in MAFLD subjects with a negative predictive value above 90%. Using the new algorithm with LFRI thresholds recommended by the manufacturer, the number of subjects classified into ALF risk groups (low, intermediate, or high) differed significantly when compared with the reference algorithm (p = 0.001), with moderate agreement between them (weighted kappa (95% CI) = 0.59 (0.41–0.77)). To improve the performance of the LFRI-based algorithm, we modified cut-off points based on ROC curves obtained by dividing the study population according to the reference algorithm and observed no difference between algorithms (p = 0.054) in categorizing ALF risk, with a slight increase in the total agreement (weighted kappa (95% CI) = 0.63 (0.44–0.82)). Our findings suggest that using the novel LFRI as a second-line test may represent a potential alternative for liver fibrosis risk stratification in MAFLD patients; however, modified cut-offs are needed to optimize its performance. [ABSTRACT FROM AUTHOR]

This document discusses the measurement uncertainty (MU) of serum ferritin, a key performance indicator for laboratory measurements. The authors collected data from four commercial measuring systems and calculated the standard MU associated with clinical samples. The results showed that the Architect i2000 had the best performance in terms of MU on clinical samples. However, without an objectively defined analytical performance specification (APS), it is difficult to determine the suitability of this figure. The authors suggest using the 'state of the art-based' (SoA) APS model to temporarily define APS for MU. The data from this study can help provide information for defining APS for clinical sample measurements. The authors conclude that the practical application of the traceability concept and the procedural implementation of calibration traceability are often poorly managed, and comparative information like this study should be used to improve the analytical quality of measuring systems. [Extracted from the article]

C-reactive protein (CRP) is a cytokine-mediated acute phase reactant with a recognized role in inflammatory conditions and infectious disease. In coronavirus disease 2019 (COVID-19), elevated CRP concentrations in serum were frequently detected and significantly associated with poor outcome in terms of disease severity, need for intensive care, and in-hospital death. For these reasons, the marker was proposed as a powerful test for prognostic classification of COVID-19 patients. In most of available publications, there was however confounding information about how interpretative criteria for CRP in COVID-19 should be derived, including quality of employed assays and optimal cut-off definition. Assuring result harmonization and controlling measurement uncertainty in terms of performance specifications are fundamental to allow worldwide application of clinical information according to specific CRP thresholds and to avoid risk of patient misclassification. [ABSTRACT FROM AUTHOR]

From External Quality Assessment data, current harmonization of CRP measuring systems appears to be satisfactory, the inter-assay CV being well below 10%. The inter-method variability is even better (close to 3%) when the widely used measuring systems are compared at CRP concentrations employed as cut-off for detecting sub-clinical infection (i.e., 10.0 mg/L) and measurement variability estimated, according to ISO 20914:2019 Technical Specification, from the intermediate within-lab reproducibility of 6-month consecutive measurement data. According to the state-of-the-art model (which is better suited for CRP), the maximum allowable measurement uncertainty (MAU) for CRP measurement on clinical samples with 10.0 mg/L concentrations is 3.76% (desirable quality). As measurement uncertainty (MU) of the only available reference material (ERM-DA474/IFCC) is ∼3%, to fulfil desirable MAU on clinical samples, IVD manufacturers should work to keep the contribution of remaining MU sources (commercial calibrator and intermediate within-lab reproducibility) lower than 2.3%. [ABSTRACT FROM AUTHOR]

Selecting appropriate laboratory tests based on available evidence is central to improve clinical effectiveness and impacting on patient outcome. Although long studied, there is no mutual agreement upon pleural fluid (PF) management in the laboratory context. Given the experienced confusion about the real contribution of laboratory investigations to guide clinical interpretation, in this update, we tried to identify useful tests for the PF analysis, aiming to unravel critical points and to define a common line in requesting modalities and practical management. We performed a careful literature review and a deepened study on available guidelines to finalize an evidence-based test selection, intended for clinicians' use to streamline PF management. The following tests depicted the basic PF profile routinely needed: (1) abbreviated Light's criteria (PF/serum total protein ratio and PF/serum lactate dehydrogenase ratio) and (2) cell count with differential analysis of haematological cells. This profile fulfils the primary goal to determine the PF nature and discriminate between exudative and transudative effusions. In specific circumstances, clinicians may consider additional tests as follows: the albumin serum to PF gradient, which reduces exudate misclassification rate by Light's criteria in patients with cardiac failure assuming diuretics; PF triglycerides, in differentiating chylothorax from pseudochylothorax; PF glucose, for identification of parapneumonic effusions and other causes of effusion, such as rheumatoid arthritis and malignancy; PF pH, in suspected infectious pleuritis and to give indications for pleural drainage; and PF adenosine deaminase, for a rapid detection of tuberculous effusion. [ABSTRACT FROM AUTHOR]

Analytical performance specifications, lot-to-lot variation, measurement uncertainty, method evaluation, CLSI-ep26 Keywords: analytical performance specifications; CLSI-ep26; lot-to-lot variation; measurement uncertainty; method evaluation EN analytical performance specifications CLSI-ep26 lot-to-lot variation measurement uncertainty method evaluation e218 e220 3 10/03/23 20231001 NES 231001 To the Editor, We appreciate the attention that Bayat et al. have paid to our paper proposing an approach for determining allowable between reagent lot variation [[1]]. [Extracted from the article]

IVD manufacturers have total responsibility in terms of the traceability of marketed in vitro diagnostic medical devices (IVD-MD). This includes the provision of a quality control (QC) material as a part of the measuring system, suitable for traceability verification and alignment surveillance by end-users in daily practice. This material [to be used for the internal QC (IQC) component I as described in this paper] should have unbiased target values and an acceptability range corresponding to analytical performance specifications (APS) for suitable (expanded) measurement uncertainty (MU) on clinical samples. On the other hand, medical laboratories (by the IQC component II as described in this paper) should improve the IQC process and its judging criteria to establish a direct link between their performance, estimated as MU of provided results, and APS defined according to recommended models to apply corrective actions if the performance is worsening with the risk to jeopardize the clinical validity of test results. The participation to external quality assessment (EQA) programs that meet specific metrological criteria is also central to the evaluation of performance of IVD-MDs and of medical laboratories in terms of harmonization and clinical suitability of their measurements. In addition to the use of commutable materials, in this type of EQA it is necessary to assign values to them with selected reference procedures and to define and apply maximum allowable APS to substantiate the suitability of laboratory measurements in the clinical setting. [ABSTRACT FROM AUTHOR]

New millennium diagnostic criteria for acute myocardial infarction precipitated a revolutionary shift from an approach based primarily on electrocardiography and clinical symptoms to a strategy based on biomarkers, and preferably cardiac troponins (cTn) I and T. In the last 20 years, clinical recommendations have strengthened the role of cTn and led to the development of highly sensitive (hs-cTn) assays, which are now leading players in all current clinical practice guidelines. To optimize the clinical use of these hs-cTn assays, focus on their analytical aspects has become increasingly important, emphasizing the need for the establishment of suitable analytical performance by the definition and implementation of appropriate specifications. An accurate estimate of measurement uncertainty, together with the acquisition of the highest analytical quality when very low concentrations of hs-cTn are measured, are essential requirements and should represent a practical laboratory standard in assuring optimal clinical use. Additional goals for further improving the quality of laboratory information should be the establishment of robust data concerning biological variation of cTn and the resolution of practical challenges opposed to the harmonization of cTn I results obtained by differing commercial measuring systems. [ABSTRACT FROM AUTHOR]

Laboratories should estimate and validate [using analytical performance specifications (APS)] the measurement uncertainty (MU) of performed tests. It is therefore essential to appropriately define APS for MU, but also to provide a perspective on suitability of the practical application of these APS. In this study, 23 commonly ordered measurands were allocated to the models defined during the 2014 EFLM Strategic Conference to derive APS for MU. Then, we checked if the performance of commercial measuring systems used in our laboratory may achieve them. Most measurands (serum alkaline phosphatase, aspartate aminotransferase, creatine kinase, γ-glutamyltransferase, lactate dehydrogenase, pancreatic amylase, total proteins, immunoglobulin G, A, M, magnesium, urate, and prostate-specific antigen, plasma homocysteine, and blood red and white cells) were allocated to the biological variation (BV) model and desirable APS were defined accordingly (2.65%, 4.75%, 7.25%, 4.45%, 2.60%, 3.15%, 1.30%, 2.20%, 2.50%, 2.95%, 1.44%, 4.16%, 3.40%, 3.52%, 1.55%, and 5.65%, respectively). Desirable APS for serum total cholesterol (3.00%) and urine albumin (9.00%) were derived using outcome-based model. Lacking outcome-based information, serum albumin, high-density lipoprotein cholesterol, triglycerides, and blood platelets were temporarily reallocated to BV model, the corresponding desirable APS being 1.25%, 2.84%, 9.90%, and 4.85%, respectively. A mix between the two previous models was employed for serum digoxin, with a 6.00% desirable APS. In daily practice by using our laboratory systems, 16 tests fulfilled desirable and five minimum APS, while two (serum albumin and plasma homocysteine) exceeded goals, needing improvements. [ABSTRACT FROM AUTHOR]

Elevated liver enzyme activity may be associated with metabolic syndrome (MetS); however, it is not included in the MetS definition for children. Postprandial changes in the levels of biochemistry tests are related to manifestations of metabolic abnormalities. We assessed the association between fasting and postprandial liver enzymes levels with MetS and elevated hemoglobin A1c (HbA1c) in children aged 9–11. The study included 51 girls and 48 boys, all presumably healthy. In all participants' anthropometric indices, fasting glucose, insulin, lipid profile and HbA1c were measured. Enzymes, including alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT), were assayed in fasting and postprandial states. Individuals were divided into subgroups: with (MetS(+): n = 26); without MetS (MetS(−): n = 73); with HbA1c levels ≤ 5.3% (n = 39); and ≥5.7% (n = 11). Elevated fasting GGT levels were found in 23% of MetS(+) children and rarely in MetS(−) children; increased postprandial GGT was noted in 35% of MetS(+) individuals. Postprandial GGT changes tend to predict MetS (OR = 1.16; p = 0.092). Increased fasting ALT was found rarely in MetS(+) children, but did not occur in MetS(−) children. HbA1c ≥ 5.7% occurred rarely and neither fasting ALT nor GGT were related to elevated HbA1c. However, postprandial change of ALT was a good positive predictor of increased HbA1c (OR = 1.33; p = 0.021). Postprandial GGT performs better as an indicator of metabolic syndrome occurrence, and instead postprandial ALT may predict prediabetes in prepubertal children. [ABSTRACT FROM AUTHOR]

In the recent years, new CRP candidate reference materials (RM) were nominated to be listed in the Joint Committee for Traceability in Laboratory Medicine (JCTLM) database. In other words, it was unclear if the new CRP candidate RM providers proposed an alternative calibration hierarchy to that currently used in the clinical community, already listed on the JCTLM database [[10]]. Keywords: C-reactive protein; metrological traceability; result comparability; standardization EN C-reactive protein metrological traceability result comparability standardization 1537 1539 3 07/18/23 20230801 NES 230801 Of current inflammatory markers identified, C-reactive protein (CRP) has the assay and biological characteristics most conducive to use in clinical practice [[1]]. [Extracted from the article]

The Joint Committee for Traceability in Laboratory Medicine (JCTLM) currently lists the secondary commutable certified reference material (CRM) ERM DA-474/IFCC (DA-474) "C-Reactive Protein in Human Serum" and two generic immunoassay-based method principles as the basis for implementing the metrological traceability of C-reactive protein (CRP) measurements by end-user measurement procedures used by medical laboratories. The current metrological traceability has produced well harmonized results for clinical samples among different end-user measurement procedures. New higher-order pure substance and secondary commutable CRMs have been nominated for listing by the JCTLM. However, the data supporting performance of these new candidate CRMs, including use of new mass spectrometry based candidate reference measurement procedures (RMPs), was not clear regarding the influence that introducing these new CRMs would have on the current well harmonized results achieved with the existing metrological traceability to DA-474. The clinically relevant CRP measurand in blood serum or plasma is a pentamer of identical subunits, which adds complexity to the application of higher-order CRMs and RMPs. The JCTLM convened a workshop in December 2022 to review the appropriate implementation of metrological traceability of CRP measurements. The workshop consensus was that the extent-of-equivalence data must include considerations about the impact of a new CRM when used for its intended purpose in the calibration hierarchies of existing end-user measuring systems; and that a new RMP must compare results with another existing well validated candidate RMP or with a globally available end-user measurement system. [ABSTRACT FROM AUTHOR]

Appropriateness in Laboratory Medicine has been the object of various types of interventions. From published experiences, it is now clear that to effectively manage the laboratory test demand it is recommended to activate evidence-based preventative strategies stopping inappropriate requests before they can reach the laboratory. To guarantee appropriate laboratory test utilization, healthcare institutions should implement and optimize a computerized provider order entry (CPOE), exploiting the potential of electronic requesting as "enabling factor" for reinforcing appropriateness and sustaining its effects over time. In our academic institution, over the last 15 years, our medical laboratory has enforced various interventions to improve test appropriateness, all directly or indirectly based on CPOE use. The following types of intervention were implemented: (1) applying specific recommendations supported by monitoring by CPOE as well as a continuous consultation with clinicians (tumour markers); (2) removing outdated tests and avoiding redundant duplications (cardiac markers, pancreatic enzymes); (3) order restraints to selected wards and gating policy (procalcitonin, B-type natriuretic peptide, homocysteine); (4) reflex testing (bilirubin fractions, free prostate-specific antigen, aminotransferases, magnesium in hypocalcemia); and (5) minimum retesting interval (D-Dimer, vitamin B12, C-reactive protein, γ-glutamyltranspeptidase). In this paper, we reviewed these interventions and summarized their outcomes primarily related to the changes in total test volumes and cost savings, without neglecting patient safety. Our experience confirmed that laboratory professionals have an irreplaceable role as "stewards" in designing, implementing, evaluating, and maintaining interventions focused to improving test appropriateness. [ABSTRACT FROM AUTHOR]

Alignment of the new generation of Abbott Alinity -glutamyltransferase assay to the IFCC reference measurement system should be improved Table 1: -Glutamyltransferase (GGT) results on serum pools obtained by IFCC reference measurement procedure (RMP) and Alinity c GGT2 measuring system. Keywords: -glutamyltransferase; measurement uncertainty; metrological traceability; systematic error; trueness EN -glutamyltransferase measurement uncertainty metrological traceability systematic error trueness e228 e231 4 08/30/22 20220901 NES 220901 To the Editor, Serum enzymes are important for the diagnosis and monitoring of many organ-related diseases and therefore the standardization of their measurements is essential [[1]]. [Extracted from the article]

In medical laboratories, the appropriateness challenge directly revolves around the laboratory test and its proper selection, data analysis, and result reporting. However, laboratories have also a role in the appropriate management of those phases of total testing process (TTP) that traditionally are not under their direct control. So that, the laboratory obligation to act along the entire TTP is now widely accepted in order to achieve better care management. Because of the large number of variables involved in the overall TTP structure, it is difficult to monitor appropriateness in real time. However, it is possible to retrospectively reconstruct the body of the clinical process involved in the management of a specific laboratory test to track key passages that may be defective or incomplete in terms of appropriateness. Here we proposed an appropriateness check-list scheme along the TTP chain to be potentially applied to any laboratory test. This scheme consists of a series of questions that healthcare professionals should answer to achieve laboratory test appropriateness. In the system, even a single lacking answer may compromise the integrity of all appropriateness evaluation process as the inability to answer may involve a significant deviation from the optimal trajectory, which compromise the test appropriateness and the quality of subsequent steps. Using two examples of the check-list application, we showed that the proposed instrument may offer an objective help to avoid inappropriate use of laboratory tests in an integrated way involving both laboratory professionals and user clinicians. [ABSTRACT FROM AUTHOR]

CHE activity in serum is stable for several years if stored at temperature lower than -20 °C [[1]]. To check the quality of CHE measurements it is essential to correctly define analytical performance specifications (APS). Keywords: analytical performance specifications; biological variation; serum cholinesterase EN analytical performance specifications biological variation serum cholinesterase e177 e180 4 06/21/22 20220701 NES 220701 To the Editor, Measurements of serum cholinesterase (CHE, also called pseudocholinesterase) catalytic concentrations are primarily used as a test of liver function and, less frequently, as an indicator of possible organic phosphorous insecticide poisoning in agriculture or organic chemical industry workers [[1]]. Supplemental Figure shows the individual mean and absolute range of CHE in evaluated subjects and Table 2 displays the derived results, including APS derived from BV data. [Extracted from the article]

This letter, published in the Annals of Clinical Biochemistry, discusses the measurement uncertainty of serum total carbon dioxide (tCO2) and the impact of closing analyser lids on reducing this uncertainty. The authors conducted experiments using different generations of chemistry analysers and found that closing lids did not consistently reduce measurement variance. They also compared their results to performance specifications for maximum allowable standard measurement uncertainty and found that only the Architect platform met the minimum quality goal. The authors recommend that manufacturers focus on improving the analytical quality of tCO2 measurements to reduce variability. [Extracted from the article]

Clinicians trust medical laboratories to provide reliable results on which they rely for clinical decisions. Laboratories fulfil their responsibility for accurate and consistent results by utilizing an arsenal of approaches, ranging from validation and verification experiments to daily quality control procedures. All these procedures verify, on different moments, that the results of a certain examination procedure have analytical performance characteristics (APC) that meet analytical performance specifications (APS) set for a particular intended use. The APC can in part be determined by estimating the measurement uncertainty component under conditions of within-laboratory precision (uRw), which comprises all components influencing the measurement uncertainty of random sources. To maintain the adequacy of their measurement procedures, laboratories need to distinguish aspects that are manageable vs. those that are not. One of the aspects that may influence uRw is the momentary significant bias caused by shifts in reagent and/or calibrator lots, which, when accepted or unnoticed, become a factor of the APC. In this paper, we postulate a model for allocating a part of allowable uRw to between-reagent lot variation, based on the need for long-term consistency of the measurement variability for that specific measurand. The allocation manages the ratio between short-term and long-term variation and indicates laboratories when to reject or correct certain variations due to reagent lots. [ABSTRACT FROM AUTHOR]

A relevant portion of patients with disease caused by the severe acute respiratory syndrome coronavirus 2 (COVID-19) experience negative outcome, and several laboratory tests have been proposed to predict disease severity. Among others, dramatic changes in peripheral blood cells have been described. We developed and validated a laboratory score solely based on blood cell parameters to predict survival in hospitalized COVID-19 patients. We retrospectively analyzed 1,619 blood cell count from 226 consecutively hospitalized COVID-19 patients to select parameters for inclusion in a laboratory score predicting severity of disease and survival. The score was derived from lymphocyte- and granulocyte-associated parameters and validated on a separate cohort of 140 consecutive COVID-19 patients. Using ROC curve analysis, a best cutoff for score of 30.6 was derived, which was associated to an overall 82.0% sensitivity (95% CI: 78–84) and 82.5% specificity (95% CI: 80–84) for detecting outcome. The scoring trend effectively separated survivor and non-survivor groups, starting 2 weeks before the end of the hospitalization period. Patients' score time points were also classified into mild, moderate, severe, and critical according to the symptomatic oxygen therapy administered. Fluctuations of the score should be recorded to highlight a favorable or unfortunate trend of the disease. The predictive score was found to reflect and anticipate the disease gravity, defined by the type of the oxygen support used, giving a proof of its clinical relevance. It offers a fast and reliable tool for supporting clinical decisions and, most important, triage in terms of not only prioritization but also allocation of limited medical resources, especially in the period when therapies are still symptomatic and many are under development. In fact, a prolonged and progressive increase of the score can suggest impaired chances of survival and/or an urgent need for intensive care unit admission. [ABSTRACT FROM AUTHOR]

Results are automatically calculated by the system as follows: HbA SB 1c sb (mmol/mol)=[HbA SB 1c sb ( mol/L)/total haemoglobin (mol/L)] × 1,000. A bias >1 mmol/mol for Alinity became however evident only in samples with HbA SB 1c sb values >=69 mmol/mol. Keywords: clinical governance; diabetes; HbA1c; metrological traceability; total laboratory automation EN clinical governance diabetes HbA1c metrological traceability total laboratory automation 441 450 10 02/07/22 20220201 NES 220201 Introduction There are approximately 500 million people living with diabetes mellitus (DM) worldwide [[1]]. Alinity showed a mean positive absolute bias of 0.54 mmol/mol (range: -0.4 to 2.6 mmol/mol), corresponding to a mean percentage difference of 0.87% (range: -1.13 to 2.74%). [Extracted from the article]

Previous studies reported lipase elevations in serum of COVID-19 patients trying to establish a causal link between SARS-CoV-2 infection and pancreatic damage. However, the degree and prevalence of hyperlipasemia was not uniform across studies. We retrospectively evaluated 1,092 hospitalized patients with COVID-19 and at least one available lipase result. The number and frequency of patients with lipase above the upper reference limit (URL), >3 URL, and >6 URL were estimated. Correlations between lipase values and other biomarkers of organ or tissue damage were performed to identify possible extra-pancreatic sources of lipase release. The potential prognostic role of lipase to predict death and intensive care unit (ICU) admission during hospitalization was also evaluated. Lipase was >URL in 344 (31.5%) of COVID-19 patients. Among them, 65 (5.9%) and 25 (2.3%) had a peak lipase >3 URL and >6 URL, respectively. In the latter group, three patients had acute pancreatitis of gallstone or drug-induced etiology. In others, the etiology of lipase elevations appeared multifactorial and could not be directly related to SARS-CoV-2 infection. No correlation was found between lipase and other tested biomarkers of organ and tissue damage. Lipase concentrations were not different between survivors and non-survivors; however, lipase was significantly increased (p<0.001) in patients admitted to the ICU, even if the odds ratio for lipase as predictor of ICU admission was not significant. Lipase was elevated in ∼1/3 of COVID-19 patients, but the clinical significance of this finding is unclear and irrelevant to patient prognosis during hospitalization. [ABSTRACT FROM AUTHOR]

Although being the recommended laboratory test to diagnose acute pancreatitis, serum pancreatic lipase (LIP) is among the poorly standardized laboratory tests, and laboratory stakeholders often appear to not take enough care of the quality of its measurements. Here we discuss some important issues that, if not correctly managed and solved, make misdiagnosis of acute pancreatitis by using serum LIP a real possibility. First, the current unavailability of a suitable higher-order reference material to be used as common calibrator should be filled up to definitively improve the inter-method bias. Second, knowledge of the analytical characteristics that may explain the defective performance of LIP assays should be deepened. IVD manufacturers should be more explicit in providing this information, including description of their internal protocol for transferring LIP values from internal references to commercial calibrators. Third, recommended models for accurately estimating measurement uncertainty and reliably defining analytical performance specifications for LIP measurements should be applied. Finally, investments considering alternative options for measuring LIP (e.g., targeted to the development of automated LIP immunoassays) should be warranted. All involved stakeholders (standardization bodies, higher-order reference providers, in vitro diagnostics manufacturers, and laboratory professionals) should contribute to fill the existing gap. [ABSTRACT FROM AUTHOR]

Pre-analytical plasma glucose (PG) sampling methodology may significantly affect gestational diabetes mellitus (GDM) incidence, but no studies directly examined the impact on perinatal outcomes. We compared the effect on oral glucose tolerance test (OGTT) results of using for blood sampling the traditional sodium fluoride (NaF) tubes, batched at controlled temperature, and the more effective citrate-buffered tubes, in terms of GDM diagnosis and related outcomes. We evaluated 578 pregnant women performing OGTT between 24- and 28-weeks' gestation. Paired NaF and citrate blood samples were drawn and analyzed for PG. GDM diagnosis was made by applying the 'one-step' American Diabetes Association strategy. Data on perinatal outcomes were collected in a subset of 330 women who delivered in our hospital network. Using the standard NaF approach, 69 (11.9%) GDM women were detected. Using citrate PG values, 90 women were additionally identified as GDM, increasing the GDM prevalence to 27.5%. Perinatal outcomes were analyzed according to the different diagnostic allocation (NaF-diagnosed GDM, additional citrate-diagnosed GDM, and no GDM). NaF-diagnosed GDM showed a higher incidence of large for gestational age (LGA) (p=0.034), and of cesarean and preterm delivery (p<0.01) vs. no GDM. The only outcome remaining more frequent in the additional citrate diagnosed GDM when compared with no GDM group was LGA (17.2 vs. 6.8%, p=0.025). If a health care system plans to use citrate tubes for GDM diagnosis, considerations about clinical implications are mandatory by balancing higher sensitivity in detecting a poor glycemic control with effects on outcomes to avoid "overdiagnosis". [ABSTRACT FROM AUTHOR]

This letter discusses the evaluation of a monoclonal antibody-based immunoturbidimetric assay, Elaprest Turbo, for measuring faecal pancreatic elastase-1 (PE1) on the Optilite analyser. The authors compared the performance of Elaprest Turbo with the ScheBo PE1 ELISA stool test, which is currently used in their laboratory. The results showed good diagnostic agreement between the two assays, indicating that Elaprest Turbo could be a valid alternative for rapid analysis of PE1. The authors also noted that Elaprest Turbo, based on monoclonal antibodies, may have advantages over the polyclonal antibody-based assay in terms of specificity and cross-reactivity with porcine elastase. Overall, Elaprest Turbo offers automation, improved workflow management, reduced turnaround time, and a wider linearity range for PE1 determination. [Extracted from the article]

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial disease with limited therapeutic options. The measurement of Krebs von den Lungen-6 (KL-6) glycoprotein has been proposed for evaluating the risk of IPF progression and predicting patient prognosis, but the robustness of available evidence is unclear. We searched Medline and Embase databases for peer-reviewed literature from inception to April 2020. Original articles investigating KL-6 as prognostic marker for IPF were retrieved. Considered outcomes were the risk of developing acute exacerbation (AE) and patient survival. Meta-analysis of selected studies was conducted, and quantitative data were uniformed as odds ratio (OR) or hazard ratio (HR) estimates, with corresponding 95% confidence intervals (CI). Twenty-six studies were included in the systematic review and 14 were finally meta-analysed. For AE development, the pooled OR (seven studies) for KL-6 was 2.72 (CI 1.22–6.06; p=0.015). However, a high degree of heterogeneity (I2=85.6%) was found among selected studies. Using data from three studies reporting binary data, a pooled sensitivity of 72% (CI 60–82%) and a specificity of 60% (CI 52–68%) were found for KL-6 measurement in detecting insurgence of AE in IPF patients. Pooled HR (seven studies) for mortality prediction was 1.009 (CI 0.983–1.036; p=0.505). Although our meta-analysis suggested that IPF patients with increased KL-6 concentrations had a significant increased risk of developing AE, the detection power of the evaluated biomarker is limited. Furthermore, no relationship between biomarker concentrations and mortality was found. Caution is also needed when extending obtained results to non-Asian populations. [ABSTRACT FROM AUTHOR]

Definition and fullfillment of analytical performance specifications (APS) for measurement uncertainty (MU) allow to make laboratory determinations clinically usable. The 2014 Milan Strategic Conference have proposed models to objectively derive APS based on: (a) the effect of analytical performance on clinical outcome; (b) biological variation components; and (3) the state of the art of the measurement, defined as the highest level of analytical performance technically achievable. Using these models appropriately, we present here a proposal for defining APS for standard MU for some common biochemical measurands. We allocated a group of 13 measurands selected among the most commonly laboratory requested tests to each of the three Milan models on the basis of their biological and clinical characteristics. Both minimum and desirable levels of quality of APS for standard MU of clinical samples were defined by using information obtained from available studies. Blood total hemoglobin, plasma glucose, blood glycated hemoglobin, and serum 25-hydroxyvitamin D3 were allocated to the model 1 and the corresponding desirable APS were 2.80, 2.00, 3.00, and 10.0%, respectively. Plasma potassium, sodium, chloride, total calcium, alanine aminotransferase, creatinine, urea, and total bilirubin were allocated to the model 2 and the corresponding desirable APS were 1.96, 0.27, 0.49, 0.91, 4.65, 2.20, 7.05, and 10.5%, respectively. For C-reactive protein, allocated to the model 3, a desirable MU of 3.76% was defined. APS for MU of clinical samples derived in this study are essential to objectively evaluate the reliability of results provided by medical laboratories. [ABSTRACT FROM AUTHOR]

Keywords: chloride; measurement uncertainty; metrological traceability; potassium; sodium EN chloride measurement uncertainty metrological traceability potassium sodium e129 e132 4 03/13/21 20210401 NES 210401 To the Editor, Blood electrolyte concentrations are tightly controlled by homeostatic mechanisms, with a very low intraindividual biological variability [[1]]. Importantly, despite the consistent improvement of electrolyte MU, u SB result sb for Na and Cl still exceed APS, while K widely fulfilled them, even at desirable level (i.e., 1.96%), being goals for this ion less stringent due to the relatively higher biological variability in plasma [[1]]. To be clinically useful, measurement results for these analytes should fulfil stringent analytical performance specifications (APS) for their measurement uncertainty (MU), which at minimum should not exceed 0.41% for plasma sodium (Na), 0.74% for plasma chloride (Cl), and 2.94% for plasma potassium (K), in terms of relative standard MU [[1]], [[2]], [[3]], [[4]]. [Extracted from the article]

To be accurate and equivalent, laboratory results should be traceable to higher-order references. Furthermore, their quality should fulfill acceptable measurement uncertainty (MU) as defined to fit the intended clinical use. With this aim, in vitro diagnostics (IVD) manufacturers should define a calibration hierarchy to assign traceable values to their system calibrators. Medical laboratories should know and verify how manufacturers have implemented the traceability of their calibrators and estimate the corresponding MU on clinical samples. Accordingly, the internal quality control (IQC) program should be redesigned to permit IVD traceability surveillance through the verification by medical laboratories that control materials, provided by the manufacturer as a part of measuring systems, are in the clinically suitable validation range (IQC component I). Separately, laboratories should also monitor the reliability of employed IVD measuring systems through the IQC component II, devoted to estimation of MU due to random effects and to obtaining MU of provided results, in order to apply prompt corrective actions if the performance is worsening when compared to appropriate analytical specifications, thus jeopardizing the clinical validity of test results. [ABSTRACT FROM AUTHOR]