Clinical chemistry and laboratory medicine最新文献

Objectives: Patient-based real-time quality control (PBRTQC) is an alternative tool for laboratories that has gained increasing attention. Despite the progress made by using various algorithms, the problems of data volume imbalance between in-control and out-of-control results, as well as the issue of variation remain challenges. We propose a novel integrated framework using anomaly detection and graph neural network, combining clinical variables and statistical algorithms, to improve the error detection performance of patient-based quality control.

Methods: The testing results of three representative analytes (sodium, potassium, and calcium) and eight independent variables of patients (test date, time, gender, age, department, patient type, and reference interval limits) were collected. Graph-based anomaly detection network was modeled and used to generate control limits. Proportional and random errors were simulated for performance evaluation. Five mainstream PBRTQC statistical algorithms were chosen for comparison.

Results: The framework of a patient-based graph anomaly detection network for real-time quality control (PGADQC) was established and proven feasible for error detection. Compared with classic PBRTQC, the PGADQC showed a more balanced performance for both positive and negative biases. For different analytes, the average number of patient samples until error detection (ANPed) of PGADQC decreased variably, and reductions could reach up to approximately 95 % at a small bias of 0.02 taking calcium as an example.

Conclusions: The PGADQC is an effective framework for patient-based quality control, integrating statistical and artificial intelligence algorithms. It improves error detection in a data-driven fashion and provides a new approach for PBRTQC from the data science perspective.

High quality laboratory results are critical for patient management. However, poor sample quality can impact these results and patient safety. To ensure reliable and accurate results laboratories must be aware of each analyte's stability under various storage conditions and matrices to guarantee correct and dependable outcomes. This knowledge allows laboratories to define the allowable delay between sample collection and centrifugation/analysis for all analytes to guarantee appropriate results quality and interpretation. The EFLM WG-PRE therefore established a 4-step plan to tackle this issue, aiming to standardize and harmonize stability studies for improved comparison and meta-analysis. The plan included the development of checklists and how-to guides for performing and reporting stability studies as well as a central resource of stability data. This manuscript deals with the issue of evaluating publications and incorporating them into a central resource. To evaluate stability studies, the CRESS checklist was used to structure 20 sections used to judge the quality of studies. Each section has 4 levels of quality, with scores converted to numerical values and weighted based on expert opinion. Based on this, a final score ranging from A to D was determined. The procedure was then tested on six manuscripts and checked for agreement between expert judgements. The results demonstrated that the proposed evaluation process is a useful tool to distinguish between best in class manuscripts and those of lower quality. The EFLM WG-PRE strongly believes that the provided recommendations and checklists will help improving stability studies both in quality and standardisation.

The development of microRNA (miRNA)-based biomarkers has gained significant attention due to their potential diagnostic, prognostic and therapeutic applications. However, the reproducibility of miRNA biomarker research faces unique challenges, primarily due to the influence of pre-analytical and analytical factors. The absence of standardized procedures contributes to inconsistencies across studies, alongside challenges in reference gene selection, data analysis methods and miRNA profiling platforms. Inter-laboratory comparison trials, or ring trials, offer a strategic approach to address technical and biological variability in miRNA biomarker studies. These trials promote standardization, identify sources of variability and strengthen the correlation between miRNAs and clinical outcomes. Despite their underutilization in miRNA biomarker research, ring trials represent a valuable tool for enhancing reproducibility and expediting the translation of miRNA-based biomarkers into clinical applications.

Objectives: Efficient and timely transportation of clinical samples is pivotal to ensure accurate diagnoses and effective patient care. During the transportation process, preservation of sample integrity is crucial to avoid pre-analytical aberrations on laboratory results. Here, we present a comparative analysis between a two-step Tempus600 hub solution single-tube and a one-step, container-based pneumatic transport system (PTS) from Airco, for the in-house transportation of blood samples.

Methods: Ten blood samples from healthy volunteers were split in 10 mL collection tubes filled at full or half capacity for transportation with the two PTS (about 250 m). To compare the impact of transportation, markers of hemolysis such as lactate dehydrogenase (LDH), potassium (K⁺), and the hemolysis index (HI), were determined. Additionally, differences in HI in routine samples and repeated transportation was investigated. To assess and compare the mechanistic impact profiles, we recorded the acceleration profiles of the two PTS using a shock data logger.

Results: Transportation using the Tempus600 hub solution resulted in 49 and 46 % higher HI with samples filled to total or half capacity, respectively. Routine samples transported with the Tempus600 hub solution showed a higher median HI by 23 and 33 %. Additionally, shock logger analysis showed an elevated amount of shocks (6.5 fold) and shock intensities (1.8 fold).

Conclusions: The Tempus600 hub solution caused an increased number of unreportable LDH or K⁺ results based on the hemolysis index. However, it was only statistically significant for LDH (p<0.01 and p<0.08) - while the comparisons for K⁺ were not statistically significant (p<0.28 and p<0.56).

Objectives: Harmonization has been recommended by the International Organization for Standard (ISO) to achieve equivalent results across in vitro diagnostic measurement devices (IVD-MDs). We aim to evaluate the effectiveness of Bland-Altman plot-based harmonization algorithm (BA-BHA) created in this study and compare it with weighted Deming regression-based harmonization algorithm (WD-BHA) proposed in ISO 21151:2020.

Methods: Eighty patient sera were used as the harmonization reference material (HRM) to develop IVD-MD-specific harmonization algorithms. Another panel of 40 patient sera was used to validate the effectiveness of harmonization algorithms. We compared regression slopes, intercepts, Bland-Altman plot layouts, percent differences, limits of agreement (LoAs), between-method coefficients of variation (CV) before and after harmonization.

Results: After harmonization by WD-BHA, acceptable slopes and intercepts between measured values and HRM targets were observed in weighted Deming regression, but not in Passing-Bablok analysis. Mean differences were -5.5 to 5.0 % and differences at specific levels were -33.9 to 23.9 %. LoAs were -64.6 to 74.6 %. Between-method CV was 22.9 % (±12.9 %). However, after harmonization by BA-BHA, both weighted Deming and Passing-Bablok regressions equations presented harmonized results. Mean differences were -0.3 to 0.2 % and differences at specific levels were -1.1 to 1.6 %. LoAs were -23.3 to 23.2 %. Between-method CV was 8.4 % (±4.0 %). The data points were evenly distributed at both sides of the mean in Bland-Altman plots.

Conclusions: The inequivalence of test results between different methods can be improved but unacceptable analytical differences at specific levels may be hidden in terms of an acceptable slope and intercept on WD-BHA. The new protocol BA-BHA may be a viable alternative to optimize the harmonization for immunoassays.

Objectives: Heparin is a highly charged polysaccharide used as an anticoagulant to prevent blood coagulation in patients with presumed myocardial infarction and to prepare heparin plasma samples for laboratory tests. There are conflicting data regarding the effects of heparin on the measurement of cardiac isoforms of troponin I (cTnI) and troponin T (cTnT), which are used for the immunodiagnosis of acute myocardial infarction. In this study, we investigated the influence of heparin on the immunodetection of human cardiac troponins.

Methods: Gel filtration (GF) techniques and sandwich fluoroimmunoassay were performed. The regions of сTnI and cTnT that are affected by heparin were investigated with a panel of anti-cTnI and anti-cTnT monoclonal antibodies, specific to different epitopes.

Results: Heparin was shown to bind to the human cardiac full-size ternary troponin complex (ITC-complex) and free cTnT, which increased their apparent molecular weights in GF studies. Heparin did not bind to the low molecular weight ITC-complex and to binary cTnI-troponin С complex. We did not detect any sites on cTnI in the ITC-complex that were specifically affected by heparin. In contrast, cTnT regions limited to approximately 69-99, 119-138 and 145-164 amino acid residues (aar) in the ITC-complex and a region that lies approximately between 236 and 255 aar of free cTnT were prone to heparin influence.

Conclusions: Heparin binds to the ITC-complex via cTnT, interacting with several sites on the N-terminal and/or central parts of the cTnT molecule, which might influence the immunodetection of analytes in human blood.

Objectives: This study aimed to evaluate discrepancies in potassium measurements between point-of-care testing (POCT) and central laboratory (CL) methods, focusing on the impact of hemolysis on these measurements and its impact in the clinical practice in the emergency department (ED).

Methods: A retrospective analysis was conducted using data from three European university hospitals: Technische Universitat Munchen (Germany), Hospital Universitario La Paz (Spain), and Erasmus University Medical Center (The Netherlands). The study compared POCT potassium measurements in EDs with CL measurements. Data normalization was performed in categories for potassium levels (kalemia) and hemolysis. The severity of discrepancies between POCT and CL potassium measurements was assessed using the reference change value (RCV).

Results: The study identified significant discrepancies in potassium between POCT and CL methods. In comparing POCT normo- and mild hypokalemia against CL results, differences of -4.20 % and +4.88 % were noted respectively. The largest variance in the CL was a +4.14 % difference in the mild hyperkalemia category. Additionally, the RCV was calculated to quantify the severity of discrepancies between paired potassium measurements from POCT and CL methods. The overall hemolysis characteristics, as defined by the hemolysis gradient, showed considerable variation between the testing sites, significantly affecting the reliability of potassium measurements in POCT.

Conclusions: The study highlighted the challenges in achieving consistent potassium measurement results between POCT and CL methods, particularly in the presence of hemolysis. It emphasised the need for integrated hemolysis detection systems in future blood gas analysis devices to minimise discrepancies and ensure accurate POCT results.

Objectives: There is a growing interest in the relevance of salivary cortisol and cortisone concentrations in stress-related research. To correctly attribute the magnitude of salivary cortisol and cortisone variation as an effect of a stressful event, a coherent understanding of the day-to-day intra-individual and inter-individual variability across the diurnal cycle of the two steroids is required. However, such information is currently lacking.

Methods: This study aimed to overcome these existing limitations by performing an investigation of the biological variation (BV) of salivary cortisol and cortisone within one day and between five days using an LC-MS/MS method. Saliva samples were collected from 20 healthy volunteers immediately after waking up, at 8:00, 12:00, 15:00, 19:00 and 23:00 on each day over five days. All samples were analyzed in duplicate in one run. Nested ANOVA was used to calculate the sums of squares for analytical and biological components of variation.

Results: The within-subject BV of salivary cortisol and cortisone (CV_I) ranged from a minimum of 29.3 and 19.0 % to a maximum of 56.5 and 49.1 %, respectively, while the between-subject biological variation (CV_G) ranged from 29.7 and 29.0 % to 51.6 and 43.6 %. The reference change values (RCVs) ranged from 96 to 245 % for cortisol and from 55 to 194 % for cortisone. A medium index of individuality was observed for both compounds at all time points.

Conclusions: This study provides updated BV estimates and RCVs for different times of day that can be used to assess the magnitude of change in biomarkers in future stress-related research.

Point-of-care testing (POCT), near-patient testing (NPT) and patient self-tests (PST) are diagnostic examinations performed at the time and place of patient care. While POCT and NPT are performed and analyzed by medical professionals, PST are based on samples and parameters directly collected and analyzed by lay users. These tests are spreading both in high income countries and in low to middle income countries as they are expected to improve healthcare efficiency and equity, by saving resources, releasing pressure from hospitals and reducing logistical barriers. However, accurate multidisciplinary assessment is mandatory to ensure that what they promise is real. We reviewed some important ethical aspects, international standards and regulations. The current risks associated with alternative ways of testing are explained by the principles of respect for patient autonomy and non-maleficence. Further evidence from multidisciplinary assessment is needed to evaluate pros and cons in light of the principles of beneficence and justice. Although POCT or NPT need common regulation and accurate provider training to ensure safe and appropriate interpretation of results, PST needs even more attention as they are subject to direct patient use. Randomized controlled trails including patient education should be conducted in order to provide reliable evidence on clinical outcomes, patient acceptance and cost-effectiveness. Mandatory regulation is needed to avoid harm and EU regulation should help different countries maintain a safe use of devices in a global population of producers and users.