Some viral infections display distinct seasonal patterns influenced by factors such as climate, human behavior, and viral characteristics. In this review, we investigated the seasonality of 15 viral infections in Korea. We analyzed viruses for which national surveillance data are available from the Korea Disease Control and Prevention Agency, including influenza virus, respiratory syncytial virus (RSV), rhinovirus, parainfluenza virus, metapneumovirus, human bocavirus, seasonal coronaviruses, enterovirus, adenovirus, norovirus, rotavirus, Japanese encephalitis virus, Hantaan virus, varicella-zoster virus, and mumps virus. In temperate climates, such as that in Korea, winter peaks are commonly observed for influenza, RSV, and norovirus infections, whereas enteroviruses are more prevalent in summer and early autumn. Parainfluenza viruses exhibit type-specific seasonality (circulating in warmer months from spring to autumn). During the coronavirus disease 2019 pandemic (2020-2021), the incidence of most respiratory and gastrointestinal viral infections analyzed in this study declined substantially owing to non-pharmaceutical interventions, such as social distancing and mask-wearing. After the preventive measures were relaxed, many viruses initially exhibited delayed or atypical seasonal peaks. However, by 2024, the seasonality of most, but not all, viral infections had largely returned to their pre-pandemic patterns. We also reviewed factors influencing viral seasonality, including climatic conditions, vector activity, human behavior, immunity, and viral genetic variation. These findings highlight the dynamic nature of viral seasonality and reinforce the importance of timely surveillance and flexible public health responses tailored to each country's epidemiological landscape.

The rapid advancement of genome sequencing has increased the detection of incidental findings (IFs) and secondary findings (SFs), raising complex ethical and practical chal-lenges in both clinical and research settings. This review examines policies, guidelines, and stakeholder perspectives on IF/SF across different jurisdictions, focusing on articles published between 2000 and 2024. We found significant variation in IF/SF reporting prac-tices, reflecting different healthcare systems and ethical frameworks. While the American College of Medical Genetics and Genomics supports proactive SF reporting, European and Canadian policies adopt more conservative approaches. Stakeholder perspectives also varied; patients generally preferred receiving results, whereas healthcare professionals' support depended on factors including actionability and patient age. Particular challenges emerged in relation to pediatric cases, with ongoing debates about balancing future au-tonomy with potential medical benefits. Implementation barriers were identified across ju-risdictions, including resource constraints, knowledge limitations, and a lack of standard-ized procedures. Despite consensus on the potential value of IF/SF reporting, inconsisten-cies in approaches and implementation challenges persist. Current evidence suggests the need for more sophisticated, context-sensitive frameworks that can accommodate differ-ent healthcare systems while maintaining consistent ethical standards. Further research is required to understand the long-term effects of different reporting approaches on patients, healthcare systems, and society.

Extended-spectrum β-lactamase (ESBL)-producing is among the most important multidrug-resistant pathogens causing bloodstream infections (BSIs). Cefotaximase (CTX-M) enzymes are the most common and highly diverse ESBL family in CTX-M-15 in group CTX-M-1 and CTX-M-14 in group CTX-M-9 are the most extensively disseminated enzymes. Multidrug-resistant strains complicate empirical therapy and increase healthcare burden globally and in Korea. We investigated the molecular epidemiology, sequence types (STs), and ESBL genotypes of bloodstream isolates in Korea and identified clinical risk factors for cefotaxime resistance.

Identifying dysmorphic red blood cells (RBCs) is critical for diagnosing glomerular diseases, as distinguishing glomerular from non-glomerular hematuria may reduce reliance on invasive diagnostics such as kidney biopsy. We aimed to enhance urinary RBC morphological classification by employing machine learning (ML) to analyze UF-5000 scattergram data.

Plasma biomarkers levels, essential for diagnosing cardiovascular diseases, may vary by ethnicity. In this international prospective study, we compared plasma biomarker levels between European and Asian patients with clinically similar acute heart failure (AHF). Data were collected on emergency admission for acute dyspnea. Blood samples were obtained within 4 hrs of presentation and analyzed for N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity troponin-T, growth differentiation factor 15, interleukin-6, and C-reactive protein levels. Overall, 907 AHF patients were enrolled; of which, 135 (15%) were Japanese, and 772 (85%) were European. NT-proBNP levels were significantly higher in Japanese than in Europeans [4,060 ng/L (interquartile range (IQR) 2,081-12,218) vs. 3,390 ng/L (IQR 1,410-7,682), =0.004]. After propensity score matching (PSM), no biomarker levels differed significantly. After stratification according to left ventricular ejection fraction (LVEF) at admission, higher NT-proBNP levels were observed in Japanese AHF patients with LVEF > 50% ( =0.02) than in European patients. After PSM, the difference was insignificant ( =0.35). In Asian and Caucasian AHF patients with similar clinical profiles, plasma cardiovascular biomarker levels did not differ significantly, regardless of LVEF, suggesting that NT-proBNP and related biomarkers can be applied across these ethnicities.

Current reference intervals for lymphocyte subpopulations are primarily based on Western populations, with limited data available for Korean children, particularly for extended subsets. We determined absolute cell counts and percentages of lymphocyte subpopulations in Korean children, according to age and sex.

Recent advancements in large language models (LLMs) have accelerated their integration into clinical domains, including laboratory medicine. The performance of LLMs in answering board-level laboratory medicine questions has not been comprehensively evaluated. Given the importance of diagnostic accuracy in this field, rigorous and objective evaluations of LLM capabilities are essential.

Accurate interpretation of whole-blood viscosity (WBV) requires population-specific reference intervals (RIs), as WBV is influenced by sex, age, and Hct. This study is the first to establish RIs for WBV using a fully automated scanning capillary tube viscometer, RHEOVIS 200 (Biorheologics, Jeonju, Republic of Korea), in Korean adults. WBV was measured in 438 adults at shear rates of 1 s (diastolic WBV) and 300 s (systolic WBV). RIs were determined using the non-parametric method according to CLSI guideline EP28-A3c, and median WBV values were compared by sex and age. At 1 s, the RIs were 20.83-38.50 millipascal-second (mPa·s) in all adults, 25.97-39.26 mPa·s in men, and 20.14-35.08 mPa·s in women. At 300 s, these were 3.74-5.50 mPa·s in all adults, 4.16-5.60 mPa·s in men, and 3.64-5.05 mPa·s in women. The median WBV was significantly higher in men than in women ( <0.01) and lower in the 20-30-yr group than in other groups ( ≤ 0.03). Sex-specific RIs are required for accurate WBV interpretation in Korean adults, and age-specific RIs require further validation. For WBV measurements using RHEOVIS 200, clinical laboratories should establish and continually verify their own RIs.

Next-generation sequencing (NGS) is increasingly applied in clinical diagnostics; however, standard workflows are frequently challenged by insufficient DNA yields in diverse clinical scenarios. Although whole-genome amplification (WGA) is used to overcome this limitation, comparative performance data on WGA kits based on different amplification mechanisms under low-input conditions remain scarce.

Our genomic understanding of lymphomas, a heterogeneous group of neoplasms, has grown exponentially. The latest World Health Organization (WHO) and International Consensus classifications reflect the importance of genetic assessment in the diagnosis and prognostication of and therapeutic decision making in lymphoid neoplasms. To address this clinical need for routinely available and timely testing, we aimed to validate the Ion AmpliSeq Liverpool Lymphoid Network Panel (IALLNP; Thermo Fisher Scientific, Waltham, MA, USA).

Cytomegalovirus (CMV) infection is prevalent worldwide. Although Korea has historically shown high CMV IgG seropositivity (>95%), declines have been reported recently. We assessed current CMV IgG seropositivity and analyzed prevailing trends in the Korean population.

Monoclonal protein (M-protein) is a crucial biomarker for diagnosing and monitoring mono-clonal gammopathies, including multiple myeloma (MM). Traditionally, electrophoresis (EP)-based methods, such as protein EP and immunofixation EP, have been widely used for M-protein detection. However, these methods can show low sensitivity and inadequate quantification of small amounts of M-protein. To overcome these challenges, EP-based methods are often combined with the quantification of serum free light chains in auto-mated immunoassays. Advances in mass spectrometry (MS) have introduced three main approaches for sample preparation: top-down, middle-down, and bottom-up. Middle-down approaches are commonly used with matrix-assisted laser desorption/ionization time-of-flight MS and liquid chromatography-electrospray ionization (LC-ESI) quadrupole time-of-flight MS, whereas the bottom-up approach is typically applied with LC-ESI Orbitrap MS. A review of studies, conducted from 2014 to 2024, on plasma cell disorders that utilized MS-based methods demonstrate improvements in the sensitivity and accuracy of M-pro-tein identification and quantification. MM remains the most frequently studied disease, with significant therapeutic advancements leading to improved outcomes. Minimal resid-ual disease has gained attention because of its correlation with better prognoses. Mono-clonal gammopathy of undetermined significance and amyloid light-chain amyloidosis are occasionally addressed, while studies on other rare diseases remain limited. This review highlights the clinical applications and advancements in MS-based methods, particularly in assessing M-protein levels for treatment responses, risk factors, and prognostic moni-toring. Given their advantages-high sensitivity and specificity, automation, cost-effective-ness, and time efficiency-MS-based methods may eventually replace EP-based methods in clinical laboratories.

An increase of group B Streptococcus (GBS) colonization in pregnant women with a parallel rise in neonatal and infant infections, were observed in Korea. We characterized antimicrobial resistance (AMR) and molecular features of GBS isolates from reproductive-aged women between 1994-2000 and 2017-2022.

Rapid pathogen identification and antibiotic-susceptibility tests (ASTs) are important for treating bloodstream infections. We compared the performance of the QMAC-dRAST and BD Phoenix M50 direct AST (dPhoenix) systems using bacterial pellets prepared from positive blood culture broth and evaluated their impact on treatment modification.

Current guidelines recommend factor IIa- or Xa-specific inhibitors over warfarin analogs for preventing thromboembolic stroke in patients with atrial fibrillation (AF). However, their plasma concentrations in Korean patients are not well understood.

Blastic plasmacytoid dendritic cell neoplasms (BPDCNs) are rare and aggressive hematologic malignancies with poorly defined molecular characteristics. Genetic data for Korean patients with this condition are scarce. We conducted the first network-based analysis of Korean patients with BPDCN, using next-generation sequencing (NGS) alongside clinical, morphological, and cytogenetic evaluations.

Fusion genes are major drivers of acute leukemia. Conventional diagnostics are limited in detecting the diverse fusions included in recently updated acute leukemia classifications. We evaluated the fusion detection performance of RNA sequencing (RNA-seq) compared with that of conventional diagnostics in patients with acute leukemia.

Transthyretin amyloidosis, a protein-misfolding disorder characterized by systemic amyloid deposition, can be classified as wild-type transthyretin amyloidosis (ATTRwt) or hereditary transthyretin amyloidosis (ATTRv), depending on the presence of transthyretin () gene variants. We examined the genetic distribution of variants in Korean patients diagnosed with ATTRv.

Alpha-fetoprotein (AFP) and its isoform AFP-L3 are well-established serum biomarkers for hepatocellular carcinoma (HCC), a common malignancy and a leading cause of cancer-related mortality worldwide. Current methods for measuring these biomarkers are primarily lectin-based assays including the liquid-phase binding assay (LiBA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), both of which have limitations in diagnostic sensitivity and clinical utility for samples with low AFP concentrations. We aimed to develop a lectin-independent LC-MS/MS method for quantifying fucosylated AFP proteins (AFP-Fuc%).