Clinical chemistry and laboratory medicine最新文献

Objectives: A recent challenge for clinical laboratories is the lack of clear guidelines for handling significant modifications of CE-marked assays. The modifications may involve, for example, extending measurement intervals, changing dilution procedures or using non-validated sample materials. The challenge arises due to the amended Regulation (EU) 2017/746 on in vitro diagnostic medical devices (IVDR), which is now poised for implementation, despite the extended transition periods. The IVDR application imposes challenges not only for diagnostic companies but also for clinical laboratories when using laboratory developed tests (LDTs), often referred to as in-house assays. In this context, a coherent and meticulously structured LDT documentation is highly beneficial. While laboratories are obliged to meet the IVDR requirements, the absence of a streamlined framework or guideline hampers the ability to gain a comprehensive overview on the requirements and possible options for their fulfilment.

Methods: To address this issue, we introduce a web based digital tool powered by an R Shiny web application. This tool facilitates a seamless implementation of IVDR requirements for LDTs across diverse laboratory environments in terms of their transparency and validity. Our approach focuses on adequate handling of significant modifications of CE-marked in vitro diagnostic medical devices (IVD).

Results: IVDRCheckR is an open-source tool that is easily accessible and free from system dependencies. The tool promotes a seamless process and a guide to enhance transparency, reliability, and validity of laboratory examination results based on LDTs. Additionally, the tool further provides modules for evaluating quality control data and quantitative method comparison data.

Conclusions: Our Shiny web application-based platform is a digitised, user-friendly tool that simplifies the documentation for LDTs according to IVDR requirements with special emphasis on solutions for handling modifications to CE-marked assays.

Objectives: The measurement of blood pH and gas analytes (BPGA), soon after birth, constitutes the first-line standard of care procedure in high-risk newborns. However, no data is available in capillary blood on perinatal bias such as gestational age (GA), weight at birth (BW), delivery mode, and gender. The aims of the present study were to investigate whether in a cohort of healthy preterm (PT) and term (T) infants BPGA were GA, BW, delivery mode and gender dependent, thus affecting BPGA reliability as diagnostic test.

Methods: We performed a prospective case-control study in 560 healthy infants (PT: n=115, T: n=445). BPGA was measured within 24-h from birth. Perinatal characteristics, outcomes, and clinical examination were also recorded.

Results: PT infants showed higher (p<0.001) carbon dioxide partial pressure (pCO₂), fraction of fetal hemoglobin (HbF), base excess (BE), bicarbonate (HCO₃), and lower lactate (Lac) levels. When corrected for delivery mode, higher (p<0.001) HbF, BE, HCO₃, and lower Lac levels were found. Similarly, higher (p<0.05, for all) pCO₂, HbF, BE, HCO₃ and lower Lac levels were found between female and male PT and T infants. Repeated multiple logistic regression analysis showed that BPGA was GA, BW, delivery mode and gender dependent.

Conclusions: The present results showing that BPGA can be affected by a series of perinatal outcomes open the way to further investigations providing longitudinal BPGA reference curves in the transitional phase, thus empowering BPGA role as a reliable diagnostic and therapeutic strategies efficacy marker.

Objectives: Chronic myeloid leukemia (CML) is characterized by the Philadelphia chromosome, leading to the BCR::ABL1 fusion gene and hyper-proliferation of granulocytes. Tyrosine kinase inhibitors (TKIs) are effective, and minimal residual disease (MRD) monitoring is crucial. Digital PCR platforms offer increased precision compared to quantitative PCR but lack comparative studies.

Methods: Eighty CML patient samples were analyzed in parallel using digital droplet PCR (ddPCR) (QXDx™ BCR-ABL %IS Kit) and chip digital PCR (cdPCR) (Dr. PCR™ BCR-ABL1 Major IS Detection Kit).

Results: Overall, qualitative and quantitative agreement was good. Sensitivity analysis showed positive percentage agreement and negative percentage agreement were both ≥90 %, and the quadratic weighted kappa index for molecular response (MR) level categorization was 0.94 (95 %CI 0.89, 0.98). MR levels subgroup analysis showed perfect categorical agreement on MR level at MR3 or above, while 35.4 % (17/48) of patient samples with MR4 or below showed discordant categorizations. Overall, Lin's concordance correlation coefficient (CCC) for the ratio of %BCR::ABL1/ABL1 converted to the International Scale (BCR::ABL1 ^IS) was almost perfect quantitative agreement (Lin's CCC=0.99). By subgroups of MR levels, Lin's CCC showed a quantitative agreement of BCR::ABL1 ^IS decreased as MR deepened.

Conclusions: Both cdPCR and ddPCR demonstrated comparable performance in detecting BCR::ABL1 transcripts with high concordance in MR3 level or above. Choosing between platforms may depend on cost, workflow, and sensitivity requirements.

Arginine vasopressin (AVP) plays a main role in maintaining the homeostasis of fluid balance and vascular tone and in regulating the endocrine stress response in response to osmotic, hemodynamic and stress stimuli. However, the difficulty in measuring AVP limits its clinical application. Copeptin, the C-terminal part of the AVP precursor, is released in an equimolar concentration mode with AVP from the pituitary but is more stable and simple to measure. Therefore, copeptin has emerged as a promising surrogate marker of AVP with excellent potential for the diagnosis, differentiation and prognosis of various diseases in recent decades. However, its application requires further validation, especially in the pediatric population. This review focuses on the clinical value of copeptin in different pediatric diseases and the prospects for its application as a potential biomarker.

Background: In laboratory setting evaluating the agreement between two measurement methods is a very frequent practice. Unfortunately, the guidelines to refer to are not free from criticisms from a statistical methodological point of view. We reviewed the Clinical and Laboratory Standards Institute guideline EP09c, 3rd ed. pointing out some drawbacks and some aspects that have not been well defined, leaving situations of uncertainty and/or of excessive subjectivity in the judgement.

Content: We have stressed the need of having replicates to estimate the systematic and the proportional biases of the measurement methods to be compared. Indeed, unequal variance of the two measurement methods gives a slope and intercept of the regression between the difference and the mean of the two values of the measurement methods to be compared that can be absolutely calculated from their means, their variances and their correlation coefficient. So, it is not possible to disentangle true from spurious biases. For laboratory professionals we have developed a worked exemplification of an agreement assessment.

Summary: We have stressed the need of other approaches than the classic Bland and Altman method to calculate the systematic and proportional biases of two measurement methods compared for their agreement in a study with replicates.

Serum and pleural fluid tumor markers are well-recognized auxiliary diagnostic tools for malignant pleural effusion (MPE). Here, we discuss some pearls and pitfalls regarding the role of tumor markers in MPE management. The following issues are discussed in this article: What is the appropriate clinical scenario for evaluating pleural tumor markers? Which tumor markers should be advocated for diagnosing MPE? Can extremely high levels of tumor markers be employed to establish a diagnosis of MPE? Does the serum-to-pleural fluid ratio of a tumor marker have the same diagnostic efficacy as the measurement of that marker alone in the pleural fluid? Can tumor markers be used to estimate the risk of specific cancers? What should be considered when interpreting the diagnostic accuracy of tumor markers? How should tumor marker studies be performed? We addressed these issues with published works, particularly systematic reviews and meta-analyses.