This issue of the International Journal of Medical Biochemistry brings together articles that reflect the expanding role of laboratory medicine in modern clinical practice. The published studies address a wide spectrum of topics, including metabolic syndrome, type 2 diabetes mellitus, hepatosteatosis, laboratory workflow monitoring, analytical performance, preanalytical variables, specimen matrix validation, and flow cytometry.
Together, these contributions emphasize that medical biochemistry is no longer limited to test measurement alone. It is a discipline that integrates biological interpretation, analytical reliability, quality management, digital tools, and clinical decision-making. Studies on oxidative stress, pharmacogenetics, vitamin D status, and inflammatory indices highlight the importance of biomarkers in understanding disease mechanisms. At the same time, articles focusing on turnaround time, HbA1c performance, blood collection tubes, and free light chain measurements underline the continuing need for standardization and quality assurance in laboratory practice.
The review on flow cytometry further demonstrates how laboratory medicine is moving toward high-dimensional and technology-driven diagnostics. Overall, this issue reflects the dynamic nature of medical biochemistry and its essential contribution to accurate diagnosis, patient monitoring, and personalized healthcare.
We would like to thank our authors for their valuable contributions to our journal, which is steadily strengthening its place in international indexes with its principles of scientific impartiality and open access, our reviewers for their meticulous evaluations that enhance our quality, and our editorial board. We hope that this issue will be beneficial to the entire medical community.

INTRODUCTION: Oxidative stress is a central feature of metabolic syndrome (MetS); however, the relationship between thiol–disulfide homeostasis and the clinical manifestations of MetS remains unclear. This study aimed to evaluate the association between thiol–disulfide balance and MetS, focusing on clinical and anthropometric parameters.
METHODS: In this cross-sectional study, 1012 adults were categorized according to MetS status. Serum native thiol, total thiol, and disulfide levels were measured, and ratio-based indices were calculated. Anthropometric measurements and blood pressure were recorded. Group comparisons, correlation analyses, and multivariate logistic regression analyses were performed.
RESULTS: Individual thiol parameters did not differ significantly between the groups. However, the disulfide-to-native thiol ratio was significantly higher in individuals with MetS and remained independently associated with MetS after adjustment for age, sex, and body mass index. Significant but modest correlations were observed between thiol–disulfide indices and obesity-related anthropometric measures.
DISCUSSION AND CONCLUSION: Ratio-based thiol–disulfide indices may better reflect systemic oxidative stress in MetS than individual parameters. These findings support the potential utility of integrated redox markers as indicators of metabolic dysfunction.

INTRODUCTION: ype 2 diabetes mellitus (T2DM) is a common chronic metabolic disorder characterized by impaired insulin secretion and insulin resistance. Metformin is the first-line pharmacological treatment for T2DM; however, substan-tial interindividual variability exists in therapeutic response. Organic cation transporters encoded by the SLC22A1 and SLC22A2 genes play a critical role in metformin transport and pharmacokinetics, and genetic polymorphisms within these genes may contribute to differences in glycemic control. The present study aimed to evaluate the association between SLC22A1 and SLC22A2 gene variants and metformin response in Turkish patients with T2DM.
METHODS: A total of 60 patients with T2DM receiving metformin therapy were included in the study and classified into adequate and inadequate glycemic control groups according to HbA1c levels (<7.0% and >7.0%). Targeted next-gener-ation sequencing analysis of the SLC22A1 and SLC22A2 genes was performed. Identified variants were evaluated under different genetic models, and genotype/allele distributions between groups were compared using Fisher’s exact test.
RESULTS: A total of 20 variants were identified in the SLC22A1 and SLC22A2 genes, including missense, intronic, synon-ymous, and one novel in-frame deletion variant. Most variants were classified as benign, whereas three variants were categorized as variants of uncertain significance. The rs683369: G>C polymorphism showed significant associations with glycemic control under the genotypic, recessive, and allelic models. The CC genotype was observed exclusively in the inadequate glycemic control group under both the genotypic (p=0.041) and recessive models (p=0.042). In ad-dition, the C allele was significantly associated with inadequate glycemic control in the allelic model (p=0.006). Addi-tionally, the novel c.1276+9_1276+16del variant demonstrated a significant allelic association with glycemic control (p=0.049). No significant associations were identified for the rs1867351: T>C or rs628031: A>G variants.
DISCUSSION AND CONCLUSION: Our findings suggest that specific SLC22A1 polymorphisms, particularly rs683369: G>C and the novel c.1276+9_1276+16del variant, may influence the glycemic response to metformin in Turkish patients with T2DM.

INTRODUCTION: Both vitamin D deficiency and hepatosteatosis are recognized as significant contributors to systemic inflammation and increased cardiovascular risk. This study aimed to investigate the associations between serum vitamin D concentrations, arterial blood pressure, and novel systemic inflammatory markers across ultrasonographically staged hepatosteatosis.
METHODS: A total of 369 patients (188 females, 181 males; mean age: 47.92±13.10 years) with sonographically con-firmed hepatosteatosis were evaluated. Participants were stratified into three groups according to the severity of liver fat accumulation: Group 1 (Grade 0; minimal), Group 2 (Grade 1; mild), and Group 3 (Grades 2–3; moderate-to-severe).
RESULTS: The mean serum vitamin D level of the cohort was 11.70±7.97 ng/mL. Pearson correlation analysis revealed a significant inverse relationship between vitamin D levels and both systolic blood pressure (SBP) (r=-0.162, p=0.002) and diastolic blood pressure (DBP) (r=-0.155, p=0.003). Statistically significant differences among steatosis grades were observed for LDH, triglycerides, uric acid, lymphocyte count (LYM), monocyte count (MONO), and the platelet-to-lymphocyte ratio (PLR) (p<0.05). Furthermore, red cell distribution width (RDW) was positively correlated with ALP (r=0.314, p=0.001), whereas PLR was negatively correlated with ALT levels (r=-0.164, p=0.02).
DISCUSSION AND CONCLUSION: Our findings suggest that significant variations in inflammatory markers such as PLR, LYM, and MONO across different grades of hepatosteatosis may reflect the complex interplay between metabolic dysfunction and systemic inflammation. Furthermore, lower vitamin D levels were associated with elevated blood pressure in patients with hepatosteatosis, highlighting a clinically relevant relationship between vitamin D status and cardiovascular risk in this population.

INTRODUCTION: Turnaround time (TAT) is a key quality indicator in laboratory medicine, but routine department-level mon-itoring is limited by fragmented data and scarce analytical resources. We aimed to develop and evaluate a modular, reproducible data analytics workflow—built in the open-source Orange visual programming platform and integrated with hospital information management system (HIMS) data—to monitor laboratory TAT, localize delays, and support quality improvement interventions.
METHODS: Approximately 3.75 million timestamped records from a 1,875-bed tertiary care hospital were extracted over three consecutive months. A six-phase Orange pipeline performed data import, concatenation, filtering, unit-level stratification, One-Class Support Vector Machine outlier exclusion, and visualization. Monthly reports were submitted to the laboratory quality committee and prompted targeted interventions. Unit-level monthly means were compared using the Friedman and Wilcoxon signed-rank tests.
RESULTS: Order-to-phlebotomy time decreased significantly across the three months (Friedman p=0.006; −17.5% with Wilcoxon p=0.005 after excluding one administrative unit). Sample reception time varied significantly (p=0.004) owing to a February peak, with no sustained net change by March (p=0.93). Total analytical TAT fell by 19.1% overall (im-munoassay: −23.7%; clinical chemistry: −22.3%)—a consistent trend that did not reach statistical significance at the test-group level (p=0.074).
DISCUSSION AND CONCLUSION: A low-code, visual Orange workflow enabled reproducible, near-real-time monthly TAT monitoring and helped target interventions, offering an accessible alternative to resource-intensive approaches.

INTRODUCTION: Accurate measurement of glycosylated hemoglobin (HbA1c) is essential for the correct diagnosis and treatment of diabetes. The Implementation Task Force of the International Federation of Clinical Chemistry and Labora-tory Medicine (IFCC-TF) recommends the standardization of HbA1c testing and its monitoring using the sigma metric model. The aim of this study was to evaluate the analytical performance of the HbA1c test using sigma metrics accord-ing to different quality specifications and to examine its impact on quality control planning.
METHODS: Coefficients of variation were evaluated using IQC materials at two levels. Bias values were calculated from 12 months of PT results. Sigma metrics were calculated according to the Clinical Laboratory Improvement Amend-ments (CLIA) 2024, National Glycohemoglobin Standardization Program (NGSP), and IFCC total allowable error (TEa) criteria. Total analytical error (TAE) was also calculated and compared with TEa limits. The Quality Goal Index (QGI) was calculated from sigma values to identify the primary source of analytical error.
RESULTS: All CV values were below 3%, except for the 12-month pooled CV1 value. The weighted mean signed bias was −0.98%, while the weighted mean absolute bias was 1.99%. Sigma metrics for the 12-month period at IQC-1 were 2.18 (IFCC), 1.64 (CLIA), and 1.09 (NGSP), indicating acceptable performance only under the IFCC criteria. For IQC-2, sigma values were 4.05 (IFCC), 3.04 (CLIA), and 2.03 (NGSP), indicating acceptable performance under all three specifications.
DISCUSSION AND CONCLUSION: The performance of the same analytical system was classified differently depending on the selected quality specification. Long-term sigma results at low concentration levels near clinical decision limits were borderline according to the IFCC criteria and unacceptable according to the CLIA and NGSP criteria, suggesting that stricter quality control strategies may be required to ensure the reliability of patient results.

INTRODUCTION: Preanalytical factors, including the choice of blood collection tubes, are a major source of laboratory errors and can affect patient care. Therefore, local verification of newly introduced tubes is essential for quality assurance and accreditation. This study aimed to evaluate the analytical comparability and clinical acceptability of Vacusera CAT Serum tubes versus established BD Vacutainer SST and Greiner Vacuette serum tubes for routine biochemistry.
METHODS: In March 2025, venous blood was collected by a single phlebotomist from 42 adults. Fifteen analytes [glucose, urea, total protein, albumin, alanine aminotransferase, aspartate aminotransferase (AST), creatine kinase (CK), C-reactive protein, calcium (Ca), phosphorus, magnesium (Mg), and uric acid by photometry; sodium (Na), potassium (K), and chloride (Cl) by indirect ion-selective electrode] were measured within the same analytical run on a Mindray BS2000M.
RESULTS: Compared with BD tubes, Vacusera showed statistically significant differences for AST (p=0.046), CK (p=0.001), Na (p<0.001), Cl (p<0.001), Ca (p=0.024), and Mg (p<0.001); compared with Greiner tubes, differences were observed for K (p=0.019) and Mg (p=0.002). Nevertheless, all analytes, except Na and Cl, fulfilled the biological variation-derived total allowable error specifications. Deming regression indicated no statistically significant constant or proportional systematic error [intercept confidence intervals (CIs) including 0; slope CIs including 1]. At predefined medical decision limits, differences between Vacusera and BD or Greiner tubes were within the reference change value limits, supporting clinically acceptable agreement.
DISCUSSION AND CONCLUSION: Despite statistically significant differences in some analytes, Vacusera CAT Serum tubes provided clinically acceptable results comparable to those obtained with BD and Greiner tubes for the tested routine biochemical parameters.

INTRODUCTION: Serum free light chain (FLC) measurement is widely used in the diagnosis and monitoring of monoclonal gammopathies. This study aimed to evaluate the analytical comparability of EDTA and lithium heparin plasma with serum for kappa and lambda FLC measurements using the Diazyme™ assay on the AU5800 analyzer.
METHODS: Twenty paired patient samples submitted for routine FLC testing were included. For each case, serum, EDTA-anticoagulated plasma, and lithium heparin plasma (Barricor tube) specimens were collected during the same phlebotomy session and analyzed in parallel. Paired comparisons were performed using the Wilcoxon signed-rank test. Agreement among serum, EDTA plasma, and lithium heparin plasma samples was assessed using Passing–Bablok regression analysis and Bland–Altman plots.
RESULTS: Kappa FLC concentrations measured in EDTA plasma did not differ from serum values (p>0.05). Lambda FLC concentrations in EDTA plasma showed a small but statistically significant difference compared with serum (p=0.037), while the kappa/lambda ratio was not significantly affected (p>0.05). In contrast, lithium heparin plasma demonstrated statistically significant differences from serum for kappa FLC (p=0.044), lambda FLC (p<0.0001), and the kappa/lambda ratio (p=0.0004). Lithium heparin plasma demonstrated broader limits of agreement and a substantially larger positive bias, particularly for lambda FLC.
DISCUSSION AND CONCLUSION: Compared with lithium heparin plasma, EDTA plasma demonstrated closer agreement with serum for kappa FLC, lambda FLC, and the kappa/lambda ratio. These findings suggest that EDTA plasma may represent a more suitable alternative specimen matrix for FLC measurement using the Diazyme assay on the AU5800 platform, although confirmation in larger studies is warranted.

Flow cytometry has evolved from early photoelectric cell-counting methods into a sophisticated, high-dimensional single-cell platform that is indispensable in biomedical research and clinical laboratories. Its historical development reflects the integration of diverse technological modalities, including hydrodynamic focusing, light scattering, fluorescence, monoclonal antibody technology, laser optics, digital electronics, and computational analysis. Conventional flow cytometry remains a cornerstone of immunophenotyping, the diagnosis of hematological malignancies, measurable residual disease assessment, transplantation immunology, selected infectious disease immune monitoring, and translational drug and vaccine development. Technological advances, including spectral flow cytometry, imaging flow cytometry, mass cytometry, microfluidic platforms, large-particle cytometry, and nanoparticle flow cytometry, have expanded its analytical scope beyond intact cells to include organoids, extracellular vesicles, and complex immune environments. The current challenge lies not only in acquiring multiparametric data but also in ensuring the reproducible design, validation, interpretation, reporting, and clinical integration of these datasets. Future developments are expected to prioritize full-spectrum acquisition, artificial intelligence-supported automated analysis, miniaturization for point-of-care use, standardized quality management, and the integration of multimodal approaches with genomic, proteomic, metabolomic, and imaging techniques. This review summarizes the past, present, and future of flow cytometry, highlighting its system architecture, analytical workflows, current platforms, clinical and research applications, quality requirements, limitations, and emerging role in precision diagnostics.