Clinical chemistry and laboratory medicine最新文献

Objectives: We examined the 0- and 2-h diagnostic performance of the Mindray high-sensitivity cardiac troponin I (hs-cTnI) assay using two predefined sex-specific 99th percentile upper reference limits (URL) in patients with normal electrocardiograms to aid in the diagnosis of myocardial infarction (MI).

Methods: Consecutive emergency department patients undergoing serial high-sensitivity cardiac troponin I (hs-cTnI) testing on clinical indication were studied in the 'Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon' (MERITnI) trial (NCT05853042). Plasma hs-cTnI testing was performed using Mindray CL1200i (investigational) and Abbott Alinity (clinical) assays.

Results: In 1,556 patients (60.7 % male, 43.3 % White, 45.8 % Black, 34.8 % chest pain), 2.7 % had type 1 MI, 2.7 % type 2 MI, and 21.5 % non-MI myocardial injury. At 0 h for all MIs (n=86), using package insert URLs and Universal Sample Bank (USB) URLs, sensitivities were 83.7 and 93.0 %. At 0/2 h for all MIs with package insert and USB URLs, sensitivities were higher with serial testing, at 95.3 and 97.7 %. Negative predictive value (NPVs) were excellent and similar for both URLs, ranging from 98 to 100 %. Substantial hs-cTnI concentration differences were observed between sex and injury types. Alinity hs-cTnI diagnostic observations were similar for both package insert and USB URLs.

Conclusions: The Mindray CL1200i hs-cTnI assay provides the relevant clinical diagnostic information to enable clinicians to deliver cost-effective care for patients to aid in the diagnosis of MI predicated on 0- and 2-h serial testing based on sex-specific 99th percentiles. Novel observations were observed for findings based on different URLs and for females and MI types.

Objectives: Accurate measurement of serum cortisol is crucial for the diagnosis and management of adrenal disorders. Thus, we have developed a novel isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC MS/MS)-based candidate reference measurement procedure (RMP) to quantify cortisol in human serum/plasma, offering higher sensitivity and reliability compared to existing RMPs.

Methods: Quantitative Nuclear Magnetic Resonance spectroscopic (qNMR) methodology has been utilized to assign the absolute content (g/g) and SI-traceability to the reference materials. A novel two-dimensional heart-cut liquid chromatography (LC) approach was implemented for the LC-MS/MS, combined with a supported liquid extraction (SLE) sample preparation protocol. A multi-day validation experiment assessed precision and accuracy. Reproducibility was assessed by comparing procedure results between two independent laboratories, and measurement uncertainty (MU) was evaluated in compliance with current guidelines.

Results: The established RMP exhibited high sensitivity, with a quantification range of 0.800-600 ng/mL (2.21-1,655 nmol/L), exceeding the ranges of existing JCTLM-listed RMPs. Intermediate precision was ≤2.6 %, and repeatability ranged from 0.9 to 1.9 % across all concentration levels. The relative mean bias ranged from -1.3 to 1.4 % for all matrices and concentration levels. Measurement uncertainties (MU) for cortisol in single measurements were ≤2.8 % regardless of the concentration level and sample type. Using the certified International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference panel, the equivalence between the candidate RMP and the Joint Committee on Traceability in Laboratory Medicine (JCTLM) listed RMPs (NRMeth 57 and NRMeth 8) was assessed, revealing excellent agreement.

Conclusions: This RMP allows for highly sensitive and reproducible determination of cortisol. The performance of the RMP facilitates the standardization of routine assays and ensures traceability in the measurement of individual patient samples.

Although significant progress has been made in recent years, some important questions remain regarding the analytical performance, pathophysiological interpretation and clinical use of cardiac troponin I (cTnI) and T (cTnT) measurements. Several recent studies have shown that a progressive and continuous increase in circulating levels of cTnI and cTnT below the cut-off value (i.e. the 99th percentile upper reference limit) may play a relevant role in cardiovascular risk assessment both in the general population and in patients with cardiovascular or extra-cardiac disease. International guidelines recommend the use of standardized clinical algorithms based on temporal changes in circulating cTnI and cTnT levels measured by high-sensitivity (hs) methods to detect myocardial injury progressing to acute myocardial infarction. Some recent studies have shown that some point-of-care assays for cTnI with hs performance ensure a faster diagnostic turnaround time and thus significantly reduce the length of stay of patients admitted to emergency departments with chest pain. However, several confounding factors need to be considered in this setting. A novel approach may be the combined assessment of laboratory methods (including hs-cTn assay) and other clinical data, possibly using machine learning methods. In the present document of the Italian Study Group on Cardiac Biomarkers, the authors aimed to discuss these new trends regarding the analytical, pathophysiological and clinical issues related to the measurement of cardiac troponins using hs-cTnI and hs-cTnT methods.

Objectives: Management of phenylketonuria (PKU) relies upon life-long monitoring of phenylalanine (Phe) in dried blood spots (DBS), thus comparability of measurements is important. The lack of harmonisation and standardisation between laboratories, combined with the variable quality of patient-collected DBS specimens, are currently preventing this from being achieved. A traceable, matrix-matched Phe certified reference material, common methodology and means to ensure patient collected DBS specimens are of consistent quality would improve comparability between laboratories.

Methods: Baseline inter-laboratory (n=15) variation of DBS Phe was determined by triplicate measurement of four DBS materials, on three days. Laboratories prepared and analysed these samples using their routine method of analysis. A sub-set of laboratories (n=5) repeated the process using a common sample preparation and instrument methodology (LC-MS/MS), and three different calibration approaches. Samples prepared on dried blood spot microsampling cards (DBS-MCs) from whole blood, value assigned for Phe concentration by National Measurement Laboratories (NML), were then analysed using the harmonised methodology.

Results: Inter-laboratory co-efficient of variation (CV) differed with calibration approach; internal calibration 27.7 %; in-house aqueous calibration 4.7 %; centrally distributed aqueous calibration, 2.1 %. Inter-laboratory CV was reduced from 8.7 to 2.1 % by using common sample preparation and LC-MS/MS methodology. No significant difference was observed between consensus and assigned values for Phe in the four materials (p>0.05).

Conclusions: This study demonstrates a simple approach to harmonising and standardising DBS Phe measurements, traceable to value assigned materials. Combined with the introduction of DBS-MCs to ensure specimen quality, clinical laboratories can achieve comparability of patient results over time.

Objectives: Pyridoxine-dependent epilepsy (PDE) is a rare genetic disorder characterized by intractable neonatal seizures responsive to pyridoxine. Diagnosis relies on quantification of α-aminoadipic semialdehyde, piperideine-6-carboxylate and pipecolic acid in urine or plasma in patients with overt symptoms. We developed and validated simple and rapid first- and second-tier methods for two recently published biomarkers of PDE (2S,6S-/2S,6R-oxopropylpiperidine-2-carboxylic acid (2-OPP) and 6-oxopiperidine-2-carboxylic acid (6-oxoPIP)) in extended newborn screening (NBS) programs from neonatal dried blood spots (DBS).

Methods: For the first-line test, DBS specimens were collected from 5,405 newborns who underwent routine NBS and analysed by FIA-MS/MS. For the second-tier test, samples were analysed by LC-MS/MS. The neonatal DBS from two patients with genetically confirmed PDE were also analysed.

Results: The reference values for NBS resulted <0.34 μmol/L for 2-OPP and <4.51 μmol/L for 6-oxoPIP. In the second-tier test, limits of detection were 0.07 μmol/L and 0.14 μmol/L, whereas limits of quantification were 0.25 μmol/L and 0.48 μmol/L, respectively, for 2-OPP and for 6-oxoPIP. The tests provided good linearity, reproducibility, accuracy and precision, with acceptable matrix effect and carry-over, according to international validation criteria. The biomarkers in DBS were stable at room temperature, +4 °C and -20 °C for one month. When assessing these biomarkers in two patients with genetically confirmed PDE, the higher sensitivity of 2-OPP as compared to 6-oxoPIP in discriminating PDE emerged.

Conclusions: The first-line and second-tier tests developed in this study highlight the potential for including PDE in the NBS panel, early diagnosis and prompt precision treatment initiation.

Objectives: This study utilized large-scale health examination data to explore gender- and age-specific reference intervals (RIs) for serum uric acid (UA) using indirect methods and assessed the consistency of different approaches.

Methods: UA data were collected from a hospital in Zhejiang Province, China. The test set covered January 2019 to December 2023, with a validation set from January to June 2024. Various methods - EP28 nonparametric (EP28-NP), parametric (EP28-P), TMC, refineR, and Kosmic - were used to establish gender- and age-specific RIs. Continuous age-based RIs were derived using the Generalized Additive Model for Location Scale and Shape (GAMLSS). Validation rates were calculated for each method using the validation set.

Results: Using EP28-NP as the benchmark, other methods showed similar UA RIs (bias ratios ≤0.375, except for one group), with Kosmic, refineR, and TMC yielding slightly higher values than EP28-NP and EP28-P. For males, UA RIs varied by age: 19-42 years (256-537 μmol/L), 43-66 years (235-513 μmol/L) and ≥67 years (214-515 μmol/L), with validation rates ranging from 94.05 to 96.50 %. Male continuous RIs declined from ages 20-79 and then gradually increased after age 80. For females, UA RIs were age-dependent: 19-48 years (169-374 μmol/L), 49-74 years (178-405 μmol/L), and ≥75 years (186-470 μmol/L), with validation rates ranging from 92.70 to 96.80 %. Female continuous RIs decreased from ages 20-48, then increased significantly from age 49 onward.

Conclusions: Three indirect methods and two EP28 methods demonstrated good consistency in establishing UA RIs. Males had higher RIs than females, and RIs showed a non-linear correlation with age.

Objectives: To study the prevalence of trisodium citrate (Na₃Citrate) contamination in hypernatraemic serum samples by direct measurement of citrate and to evaluate the performance of indirect markers for identification of Na₃Citrate contamination.

Methods: Serum citrate was measured in all hypernatraemic serum samples (sodium ≥148 mmol/L) over a three-month period. The performance of serum chloride, sodium-chloride gap, indirect ion selective electrode (ISE)-direct ISE sodium disparity and osmolar gap in identification of Na₃Citrate contaminated samples was assessed against the 'gold-standard' direct citrate measurement.

Results: In total, 27 Na₃Citrate contaminated samples were identified based on serum citrate concentration ≥1.5 mmol/L. The prevalence of citrate contamination was 3.1 % of hypernatraemic samples (n=875) and 0.017 % of all samples received for urea and electrolyte analysis (n=153,404). Most contaminated samples were from patients receiving haemodialysis (59.3 %), and the rest from inpatients. Cut-offs to give 100 % sensitivity were chloride ≤105 nmol/L (specificity 93.4 %), sodium-chloride gap ≥47 mmol/L (specificity 95.3 %), indirect ISE-direct ISE sodium disparity ≥3 mmol/L (specificity 81.9 %), and osmolar gap ≥39 mOsm/kg (specificity 2.8 %).

Conclusions: Trisodium citrate contamination is uncommon. Most contaminated samples were from patients receiving haemodialysis, likely because of contamination with citrate catheter locking solution. Screening with serum chloride or sodium-chloride gap can confidently exclude Na₃Citrate contamination in over 90 % of hypernatraemic samples, and in nearly all samples with sodium ≥155 mmol/L if metabolic alkalosis has been excluded. In the remaining samples, Na₃Citrate contamination can only be definitively confirmed or excluded by measurement of serum citrate. We propose algorithms to identify spurious hypernatraemia.

Objectives: Although existing cytopathological examination is considered essential for the diagnosis of malignant serous effusions, its accuracy is pretty low. Tumor specific protein 70 (SP70), which is highly expressed on human tumor cell membrane, was identified in our previous study. This study aimed to explore whether SP70 targeted tumor cell isolation technology with immunomagnetic beads can improve the accuracy of cytopathological examination.

Methods: Cytopathological analysis with SP70 targeted tumor cell isolation technology was used in this study. In total, 255 cases were enrolled. Serous effusions were analyzed by both existing cytopathological examination and the new cytopathological analysis concurrently.

Results: The sensitivities of existing cytopathological examination and the new cytopathological analysis were 51.26 % and 85.43 %, respectively, while the specificities were 100 % for both. This new cytopathological analysis demonstrated a higher interobserver agreement with malignant diagnosis than the existing cytopathological examination (kappa coefficient: 0.720 vs. 0.316, p<0.001). In addition, it achieved superior diagnostic efficacy for malignancy differentiation compared to existing cytopathological examination (AUC: 0.927 vs. 0.756, p<0.001). The follow-up results showed that 74 malignant cases with final clinical diagnosis were positive only with the new cytopathological analysis. Among these cases, there were 58 negative and 16 atypical by the existing cytopathological examination. In these malignant cases, 74.3 % (55/74) had been confirmed to have serosa metastasis based on radiographic evidence, and 73.7 % (28/38) harbored tumor hotspot mutations.

Conclusions: As illustrated in this work, cytopathological analysis with SP70 targeted tumor cell isolation technology can improve the accuracy of existing cytopathological examination prominently.

Objectives: We evaluated the performance of a novel flow cell morphology analyzer AUTION EYE AI-4510 for counting particles in urine.

Methods: Analytical performance was assessed according to the EFLM European Urinalysis Guideline 2023. Trueness was compared by analyzing 1.012 fresh urine samples with the AUTION EYE AI-4510 (ARKRAY, Inc., Kyoto, Japan) against phase-contrast visual microscopy. Poisson statistics were utilized in assessment of imprecision of particle counts both with quality control material and patient specimens.

Results: Relative imprecision against theoretical Poisson imprecision, R(CV), was estimated to be 1.1 for red blood cells (RBC), 1.0 for white blood cells (WBC), 0.9 for squamous epithelial cells (SEC) and 1.1 for bacteria. The agreement with visual microscopy (Cohen's weighted kappa) was 0.93 for RBC, 0.95 for WBC, 0.90 for SEC, 0.79 for non-squamous epithelial cells (NSEC), 0.67 for combined casts, 0.90 for crystals and 0.88 for bacteria. No clinically significant bias was observed. Limits of quantitation at CV=30 % reached 4 × 10⁶/L for RBC and 5 × 10⁶/L for WBC. Differentiation of urinary crystals was improved as compared to previous data on digital cuvette imaging.

Conclusions: The ARKRAY AUTION EYE AI-4510 provided a desirable imprecision, met the criteria for linearity, LoQ and carry-over, and showed an optimum comparison to visual microscopy for RBC, WBC, SEC and crystals as defined in the EFLM European Urinalysis Guideline 2023. The identification of kidney damage is recommended to be improved by using user-defined review rules. Performance of bacteria counting needs to be confirmed against urine bacterial cultures.

This scoping review focuses on the evolution of pre-analytical errors (PAEs) in medical laboratories, a critical area with significant implications for patient care, healthcare costs, hospital length of stay, and operational efficiency. The Covidence Review tool was used to formulate the keywords, and then a comprehensive literature search was performed using several databases, importing the search results directly into Covidence (n=379). Title, abstract screening, duplicate removal, and full-text screening were done. The retrieved studies (n=232) were scanned for eligibility (n=228) and included in the review (n=83), and the results were summarised in a PRISMA flow chart. The review highlights the role of healthcare professionals in preventing PAEs in specimen collection and processing, as well as analyses. The review also discusses the use and advancements of artificial intelligence (AI) and machine learning in reducing PAEs and identifies inadequacies in standard definitions, measurement units, and education strategies. It demonstrates the need for further research to ensure model validation, address the regulatory validation of Risk Probability Indexation (RPI) models and consider regulatory, safety, and privacy concerns. The review suggests that comprehensive studies on the effectiveness of AI and software platforms in real-world settings and their implementation in healthcare are lacking, presenting opportunities for further research to advance patient care and improve the management of PAEs.