Liquid chromatography tandem mass spectrometry (LC-MS/MS) is a highly sensitive analytical tool that has become the gold standard for measuring the concentrations of some steroidal hormones and therapeutic drugs in blood. However, the application of this technology in different clinical laboratories faces challenges related to the preanalytical process. In this study, we investigated how the materials used in blood collection tubes affect the measurement of serum 25-hydroxyvitamin D [25(OH)D] by LC-MS/MS. Serum samples were collected in 20 different blood collection tubes made by various manufacturers. The samples were processed under controlled conditions to simulate clinical practice, followed by measurement using an LC-MS/MS system. The data were compared with measurements obtained from a chemiluminescent enzyme immunoassay. Significant variability in measurement outcomes was observed depending on the type of blood collection tube used. Specific blood collection tubes from a manufacturer that employed specific separator gels exhibited interference, as indicated by broad peaks in chromatograms. This interference complicated the quantification of 25(OH)D. The interference was consistent across multiple samples, indicating a systemic problem related to the materials used in the blood collection tubes. These findings highlight the need to evaluate blood collection tubes from various manufacturers prior to the clinical implementation of LC-MS/MS measurements. Because LC-MS/MS has unique potential error sources, our results indicate the importance in utilizing LC-MS/MS international standards to ensure accurate and reliable results in clinical laboratories.

Mass spectrometry (MS) is emerging as a transformative diagnostic tool for plasma cell disorders, including multiple myeloma, Waldenström macroglobulinemia, and light chain amyloidosis. Traditional diagnostic methods such as serum protein electrophoresis, immunofixation electrophoresis, and serum free light chain assays, though effective, have limitations in sensitivity and specificity. These techniques may miss small monoclonal proteins or be affected by therapeutic antibody interference. Recent advances focus on top-down MS techniques, particularly matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and monoclonal immunoglobulin rapid accurate mass measurement (miRAMM). These methods analyze intact monoclonal proteins to enhance detection sensitivity and specificity. MALDI-TOF offers a streamlined workflow suitable for clinical laboratories, while miRAMM provides highly precise mass measurements, albeit requiring more sophisticated instrumentation.MS has demonstrated superior capabilities in detecting monoclonal proteins, including the ability to distinguish them from therapeutic antibodies. Additionally, MS enables structural characterization of monoclonal proteins, such as glycosylation patterns linked to amyloidosis. Notably, emerging evidence indicates that MS may match or surpass the sensitivity of molecular techniques. These include next-generation sequencing and next-generation flow cytometry, which are commonly applied to bone marrow biopsy for minimal residual disease detection, providing a less invasive alternative for disease monitoring. MS, particularly MALDI-TOF and miRAMM, represents a promising advancement in the diagnosis and monitoring of plasma cell disorders. Its high sensitivity, efficiency, and noninvasive nature support its potential to complement or replace existing diagnostic methods, improving patient care and clinical outcomes as the technology continues to evolve.

While clinical laboratories routinely perform automated chemistry assays on approved specimens (e.g., plasma and serum), the FDA has not evaluated the validity of these assays for nonapproved specimens (e.g., various body fluids). To meet College of American Pathologists' regulatory requirements, clinical laboratories must evaluate body fluid matrix effects. However, full validation studies are challenging due to time and labor demands. Therefore, a rapid and practical approach for validating body fluids benefits clinical laboratories by improving efficiency and minimizing resources utilized. Excess body fluids and plasma specimens were collected and frozen until testing was performed. Pooled body fluid specimens were spiked with a 10% spike solution (pooled plasma) containing analyte mixtures with measured concentrations. Matrix interference studies and dilution studies were performed on the Roche cobas automated (6000/8000) analyzers. The matrix effects for albumin, amylase, blood urea nitrogen, cholesterol, creatinine, glucose, lactate, lactate dehydrogenase, lipase, potassium, sodium, total bilirubin, total protein, triglycerides, and uric acid were all within acceptable limits (±20% of full recovery). However, lipase was observed to be unstable in peritoneal fluid. Dilution linearity was confirmed for all analytes in pleural, peritoneal, ascites, and synovial fluids (R2 > 0.90). Our study describes a rapid and practical approach for evaluating body fluid matrix effects in automated clinical chemistry assays. By streamlining the validation process, this approach can help laboratories maintain compliance while minimizing time and resources.

Manual morphological analysis of peripheral blood smears (PBS) with light microscopy is an essential diagnostic and monitoring tool. Recently, automated morphology analyzers have been developed that can preclassify cells using artificial intelligence algorithms. This study aims to evaluate the preliminary leukocyte classification capabilities of the MC-80 digital morphology analyzer, a novel system, in pediatric patients and compare its performance with that of manual microscopy, the current gold standard. This retrospective study was conducted at SBU Bursa Yüksek İhtisas Training and Research Hospital between September 5 and 29, 2022. Blood samples from 153 consecutive pediatric patients (age range: 0-18 years; median age: 3 years) undergoing simultaneous hemograms and PBS analyses were assessed using both the MC-80 digital morphology analyzer and manual microscopy. Spearman rank correlation coefficients indicated a high correlation for neutrophils (rho = 0.742; 95% CI: 0.661-0.807) and lymphocytes (rho = 0.745; 95% CI: 0.666-0.810) while the correlation for blast cells was significantly lower (rho = 0.079; 95% CI: -0.099-0.238). Concordance between the MC-80 and manual microscopy was minimal for monocytes (κ = 0.21; 95% CI: 0.11-0.29) and negligible for blast cells (κ = 0.08; 95% CI: 0.00-0.17). The MC-80 digital morphology analyzer shows acceptable preliminary classification for neutrophils and lymphocytes; further development is required before it can be routinely implemented in laboratory workflows.

Point-of-care (POC) diagnostic devices deliver rapid, near-patient results that drive timely clinical decisions across diverse settings (from emergency departments to home care). Their decentralized deployment mandates a rigorous, multi-phase validation strategy to ensure analytical accuracy, clinical reliability, and real-world utility before both regulatory clearance and reimbursement. We propose an expanded, integrated framework comprising 4 pillars:Analytical validity: Quantification of sensitivity, specificity, predictive values adjusted for prevalence, limits of detection, bias/imprecision, and reproducibility using Receiver Operating Characteristic (ROC) curve analysis, Bland-Altman comparison, Passing-Bablok/Deming regression, and nonparametric techniques for semiquantitative outputs.Clinical validity: Demonstration of substantial equivalence via FDA 510(k) (Class II), de novo (novel low/moderate risk), or premarket approval (PMA; Class III with Investigational Device Exemption (IDE)-supported pivotal trials) pathways, supported by prospective, multicenter clinical studies, and human-factors usability assessments in intended use environments.Clinical utility: Evidence of improved patient care from outcome-based trials (e.g., time-to-treatment and readmission rates), health-economic analyses (cost per quality-adjusted life year and budget-impact models), and patient-reported outcome measures capturing usability, satisfaction, and adherence.Regulatory alignment: Harmonization of FDA and Health Canada requirements, including ISO 14971 risk management, post-market surveillance (21 CFR 820; Medical Device Licence [MDL] vigilance), to streamline market access and payer coverage decisions. This comprehensive, staged validation pathway, from analytical benchmarks through clinical performance and utility to regulatory and reimbursement strategies, provides a practical roadmap for innovators, clinicians, and regulators. Embedding real-world evidence and coordinating US and Canadian frameworks accelerates the adoption of safe, effective, and value-based POC diagnostics, fostering better patient outcomes, and supporting modern precision medicine.

Spectrophotometric testing to detect sample hemolysis is available from central laboratory chemistry analyzers. While the cause and preventative measures are known, hemolysis continues to be a common preanalytical error, especially for specimens collected from the emergency department (ED) and intensive care units (ICUs) where point-of-care analyzers are commonly used for whole blood electrolyte testing. Recently, these analyzers have employed technology to detect hemolysis directly on whole blood samples. Experienced laboratorians and physicians from the clinical laboratory, ED, adult and neonatal ICUs provide a summary of the medical importance of in vitro hemolysis. Causes for in vivo hemolysis are summarized as it is indistinguishable from in vitro hemolysis from routine laboratory analysis. The detection of hemolysis by clinical laboratories is discussed from the American and European perspectives. In vivo hemolysis can occur due to genetic abnormalities, hemoglobinopathies that cause red cell lysis, and mechanical circulatory support. There are many causes of in vitro hemolysis. Patients in the ED and ICU are particularly vulnerable to erroneous laboratory data such as potassium. Incorrectly treated patients can lead to significant medical consequences. Within the clinical laboratory, there are recommendations made by accrediting bodies, but none are mandatory, and the implementation of the hemolysis index testing is not universal. Recommendations have been authored regarding the need for education for prevention, performance of hemolysis detection testing, defining levels of hemolysis reporting, periodic monitoring of hemolysis detection performance, and laboratory reporting practices for high and normal potassium test results.