Clinical chemistry and laboratory medicine最新文献

Objectives: This study aims to explore the biological variability of calcium homeostasis biomarkers, including calcium, phosphate, magnesium, 25-OH vitamin D, 1,25-OH vitamin D, and parathyroid hormone (PTH), and to develop a model that predicts PTH concentrations based on these parameters.

Methods: Thirty healthy volunteers were sampled on a weekly basis over a period of 10 weeks. Each sample was analyzed in duplicate. Statistical methods included estimating within- and between-subject biological variation (CV_I, CV_G) using ANOVA with outlier removal and a Bayesian model. A linear mixed-effects model (LMM) was used to estimate 95 % prediction intervals for PTH as a function of calcium, phosphate, and 25-OH vitamin D in healthy participants. The effect of applying this prediction model in routine practice was estimated using data from the Laboratory Information System.

Results: Estimated CV_I from ANOVA and the Bayesian model was: PTH, 18.0 % and 17.4 %; calcium, 1.7 % and 1.6 %; phosphate, 9.3 % and 9.3 %; 25-OH vitamin D, 4.7 % and 7.2 %; and 1,25-OH vitamin D, 16.2 % and 17.1 %. The LMM indicated the best 95 % prediction interval for PTH included calcium (PTH (pmol/L)=exp(3.46-2.67·ln(Ca (mmol/L)) ± Z·0.29)) and did not improve with phosphate and/or 25-OH vitamin D. Compared with conventional reference intervals, this model flagged 56 % vs. 41.6 % of routine PTH/calcium results, respectively.

Conclusions: Similar CV_I data were obtained using two different methods. A predictive model can be used to predict concentrations for co-regulated biomarkers, potentially enhancing sensitivity in identifying non-physiological results and facilitating clinicians' awareness of conditions affecting calcium homeostasis.

Objectives: Voriconazole is an antifungal agent measured in serum and plasma for therapeutic drug monitoring. This study aimed to develop a robust isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) reference measurement procedure (RMP) to ensure accurate and reliable quantification in compliance with metrological standards.

Methods: A commercially available voriconazole material, traceable to the International System of Units (SI), characterized by quantitative nuclear magnetic resonance spectroscopy (qNMR), served as the primary reference material. Chromatographic separation was achieved using a Raptor Biphenyl column, and isotope-labeled voriconazole was utilized as the internal standard. The candidate RMP was validated for selectivity, matrix effects, linearity, precision, accuracy, sample stability, and measurement uncertainty.

Results: The method's selectivity was successfully demonstrated, with no interfering signals observed at the retention time of voriconazole. Assessment of matrix effects revealed no significant differences in slopes across native serum, analyte-free human serum, and Li-hep plasma, confirming the absence of matrix-derived interferences. Intermediate precision was ≤3.7 %, repeatability was ≤2.3 %, and accuracy showed a mean bias ranging from -0.7 to 2.7 % across all matrices and concentration levels. Relative bias for the lower limit of the measuring interval (LLMI) was 1.7 %, with a coefficient of variation (CV) for intermediate precision of 4.3 %. Expanded measurement uncertainties (k=2) for target value assignment (n=6) ranged from 1.4 to 3.4 %.

Conclusions: This validated ID-LC-MS/MS-based RMP proved to be selective, precise, accurate, and reliable for the quantification of voriconazole in human serum and plasma. The RMP demonstrated high accuracy and precision, along with suitable measurement uncertainty, meeting all relevant requirements for an RMP. These findings support the method's suitability for use in establishing target values and ensuring accuracy in clinical laboratories.

Objectives: 5α-dihydrotestosterone (DHT) is a potent androgen, related to male sexual development and irreversibly synthesized from testosterone via 5α-reductase. Dysfunctions in the 5α-reductase system, locally or globally, can have substantial health impacts; measurement of both DHT levels and the testosterone-DHT ratio are thus important for diagnosis and treatment monitoring. For that reason, an isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC MS/MS)-based candidate reference measurement procedure (RMP) to quantify DHT in human serum/plasma was developed.

Methods: We utilized certified primary reference material for DHT provided by the National Measurement Institute of Australia (NMIA) to calibrate our assay and ensure SI (International System of Units) traceability. To mitigate matrix effects and prevent the co-elution of interferences, two-dimensional heart-cut chromatography was employed for LC-MS/MS, in combination with a solid phase extraction (SPE) sample preparation protocol. Selectivity was determined by spiking the prepared internal standard with possibly interfering substances such as the inactive isomer 5β-DHT and other similar compounds. Comparison of standard line slopes was performed to evaluate matrix effects. Precision and accuracy were assessed via a multi-day validation experiment, and variability components estimated using analysis of variance (ANOVA)-based variance component analysis (VCA). Measurement uncertainty (MU) was evaluated in compliance with current guidelines.

Results: This RMP was suitable for analyzing DHT within the range of 0.0160-2.76 ng/mL (0.0551 nmol/L-9.50 nmol/L), demonstrating selectivity, sensitivity and matrix-independence. Intermediate precision was ≤2.1 %, repeatability was ≤1.6 % across all concentration levels, and relative mean bias ranged from -2.2 to 2.5 %, across matrices and concentrations. Expanded MU for reference value assignment (n=6) was ≤2.8 %, irrespective of concentration or sample type.

Conclusions: This RMP exhibited high analytical performance for DHT quantification and met requirements for measurement uncertainty. Additionally, it enabled differentiation between the 5α-DHT and 5β-DHT isomers. Consequently, this RMP is suitable for routine assay standardization and clinical sample evaluation.

Objectives: Dehydroepiandrosterone (DHEA) is a steroid prohormone and important precursor for estrogen and testosterone biosynthesis. For differential diagnosis of sexual development disorders (e.g., polycystic ovary syndrome, congenital adrenal hyperplasia), accurate measurement of DHEA in clinical testing is essential. To address that need for high-quality, reproducible assays, an isotope dilution-liquid chromatography (LC)-tandem mass spectrometry (MS/MS)-based candidate reference measurement procedure (RMP) for the quantification of DHEA was developed and validated.

Methods: A certified primary reference material from the National Measurement Institute of Australia (NMIA), was used for DHEA assay calibration and to ensure traceability to the International System of Units (SI). Two-dimensional heart-cut chromatography was employed for LC-MS/MS in combination with a solid phase extraction sample preparation protocol, to mitigate matrix effects and prevent interference coelution. Selectivity was evaluated by spiking either the analyte or internal standard with potential interferents, such as dehydroepiandrosterone-sulfate, testosterone, and similar steroid compounds. For the evaluation of matrix effects, standard line slopes of various matrices were compared. Precision and accuracy were assessed via a multi-day validation experiment, and variability components were estimated using variance component analysis. Measurement uncertainty was evaluated in compliance with current guidelines.

Results: This candidate RMP proved suitable for the analysis of DHEA in the measurement range of 0.0800-36.0 ng/mL (0.277-125 nmol/L). Predefined requirements for sensitivity and selectivity were fully met, and independence from matrix effects was demonstrated successfully. Across all tested concentration levels, intermediate precision was ≤1.5 % and repeatability was ≤1.0 %, while the relative mean bias ranged from -1.1 to 0.1 %. Regardless of DHEA concentration or sample type, the expanded measurement uncertainty for reference value assignment (n=6) was ≤1.7 %.

Conclusions: This isotope dilution-LC-MS/MS-based candidate RMP for DHEA in human serum and plasma met pre-defined analytical performance requirements such as precision, specificity and measurement uncertainty, and showed superior selectivity towards several potential interferents tested. It is suitable for application in clinical sample evaluation and routine assay standardization.

Laboratory medicine lies at the core of modern healthcare, enabling timely diagnosis, effective patient monitoring, and increasingly personalized therapeutic strategies. Over the past decades, automation has profoundly reshaped the role of clinical laboratories, substantially enhancing their contribution to clinical outcomes, operational efficiency, and the overall sustainability of healthcare systems. More recently, laboratory automation has emerged as a cornerstone of value-based laboratory medicine, representing not merely a technological upgrade but a strategic transformation of laboratory practice aimed at delivering measurable value to patients and healthcare stakeholders. Although automation has long been established in clinical chemistry and immunoassays, its scope is now expanding to molecular diagnostics and mass spectrometry - two disciplines that are central to precision medicine. Looking ahead, the convergence of automation, digitalization, and artificial intelligence is driving the emergence of hyperautomation in laboratory medicine. Within this paradigm, laboratories evolve from isolated testing units into integrated diagnostic hubs, in which results from multiple laboratory disciplines are harmonized and contextualized to effectively support clinical decision-making.

Background: Method-comparison studies in laboratory medicine are routinely interpreted using regression-based or Bland-Altman analyses. Although useful descriptively, these statistical procedures are frequently misapplied to infer "agreement", "equivalence", or "interchangeability". Such interpretations overlook essential metrological conditions - including the definition of the measurand, the traceability chain, and measurement uncertainty - leading to misconceptions with potential clinical consequences.

Content: This Opinion Paper clarifies the distinct meanings of four metrological concepts that are often treated as synonyms: comparability, compatibility, equivalence, and interchangeability. We explain why numerical similarity or statistical association does not establish metrological relatedness, and outline the specific requirements for each concept. Comparability requires a shared measurand and calibration hierarchy; compatibility requires differences smaller than the combined uncertainty; equivalence requires clinically irrelevant residual differences; and interchangeability requires stability of clinical decisions when substituting one measuring system for another. We also discuss familiar sources of misinterpretation, including ambiguous definitions of the measurand, incomplete traceability chains, and uncritical reliance on regression- or bias-based summaries.

Summary and outlook: Distinguishing among comparability, compatibility, equivalence, and interchangeability is essential for the metrological interpretation of method-comparison studies and for ensuring safe analytical and clinical decision-making. Integrating these concepts explicitly into study design, harmonisation strategies, and reporting practice will strengthen traceability implementation, prevent erroneous claims of "agreement", and support more reliable patient care.

Objectives: To establish evidence-based analytical performance specifications (APS), specifically allowable total error (TE_a), for five fundamental semen analysis parameters (sperm concentration, progressive motility, total motility, morphology, and vitality) in China utilizing the state-of-the-art model, and to compare these specifications with existing international benchmarks.

Methods: We examined national external quality assessment (EQA) data from 2019 to 2025, encompassing 315 laboratories across 30 provinces in China. TE_a was calculated using the state-of-the-art model as half the 10th-90th percentile range of result deviations from assigned values. Given that the participant count was below 100 from 2019 to 2022, this study eventually utilized data from 2023 to 2025 for the calculation of TE_a. The pass rate of participating laboratories was evaluated against the established TE_a criteria.

Results: The established TE_a values as follows: sperm concentration, 34.3 %; progressive motility, 26.9 % (for assigned value ≤40 %) and 13.5 % (>40 %); total motility, 26.3 % (≤50 %) and 10.5 % (>50 %); morphology, 67.7 %; vitality, 24.6 % (≤60 %) and 7.9 % (>60 %). The pass rates for all parameters in recent EQA cycles were approximately 80 %, supporting the practical achievability of the proposed specifications. Comparisons showed that the derived TE_a values are generally consistent with or more refined than previous state-of-the-art and biological variation-based standards.

Conclusions: This study provides the first large-scale, evidence-based TE_a for semen analysis in China. The stratified TE_a for motility and vitality based on clinical thresholds, improves diagnostic accuracy. The proposed specifications are practical, achievable, and clinically relevant, providing a consistent foundation for quality assurance in reproductive medicine laboratories.

The secondary scientific use of routine laboratory data will increasingly rely on LOINC as a semantic standard, particularly within the European Health Data Space (EHDS). LOINC enables the aggregation of large data sets from clinical care for research purposes, particularly in epidemiology. However, current approaches to semantic standardisation largely neglect metrological aspects - in particular, the considerable limitations of analytical standardisation for many fundamental analytes and the resulting scatter of result values across different assays that use common LOINC codes. This incomplete harmonisation leads to statistical uncertainty that must be taken into account when quantitative conclusions - such as diagnostic thresholds for analytes - are derived from aggregated, LOINC-derived data sets. In this opinion piece, we propose using the extensive global data pool generated by external quality assessment (EQA) programs to finally annotate LOINC codes with a sound and useful uncertainty metric. This represents secondary scientific use of EQA data that is analogous to and supports the secondary use of routine diagnostic data from patient care for research. With a proof-of-concept analysis, we demonstrate the feasibility of this approach, which offers a wide range of design options. We suggest that consortia of EQA providers, coding institutions, scientific societies, and the IVD industry could advance precision research through this concept. It is noteworthy that the proposed annotation strategy - linking semantic test codes to uncertainty metrics based on EQA data - is not limited to LOINC as a semantic coding system.