Laboratory medicine最新文献

Introduction: To ensure adequate quality of clinical samples, laboratories must control samples' postanalytical preservation. We checked the stability limit of lactate dehydrogenase (LDH) and confirmed the 72-hour limit the manufacturer proposes, then evaluated sample stability under our working conditions using new recommendations for stability studies.

Methods: Leftover outpatient samples were randomly selected. Serum tubes with separator gel were used for primary sample collection. In a preliminary study of samples from 6 patients, we made determinations at baseline, 24, 48, and 72 hours for aliquots stored at room temperature and refrigerated. An extended study in refrigerated samples was performed on 10 samples of leftover serum at baseline and 12, 24, 36, 48, 60, and 72 hours.

Results: We found no substantial variation in samples at room temperature. In the extended study, an LDH decrease of 1.5% per day is expected up to 72 hours based on the formula PD% = 0.064 ×time [h].

Discussion: The available literature on stability studies is extensive and varies in terms of working methodology. Therefore, laboratories should follow recommendations from standardized and updated documents. We modified manufacturer stability recommendations by reducing the stability of refrigerated LDH samples in our laboratory automation system from 72 hours to 48 hours.

Introduction: This prospective study assessed relationships between COVID-19, humoral immunity, and common laboratory test results.

Methods: Blood and urine were collected from adults with clinical SARS-CoV-2 test results before August 2021: nucleic acid amplification (NAA) tests and antinucleocapsid protein (αN) serology. Measurements were made of αN and 13 laboratory tests, and results were compared across groups defined by NAA and αN status.

Results: Glycated hemoglobin (HbA1c) and platelet counts were clinically significantly higher among individuals who had COVID-19 than in individuals without evidence of COVID-19. Hemoglobin was more abnormal among patients without evidence of COVID-19. Glycated hemoglobin results were also much higher among patients with prior positive NAA and current or prior positive αN results than in individuals with negative αN results. No other statistically significant associations between NAA or αN and abnormal laboratory results were found.

Discussion: Elevated HbA1c results were associated with prior positive NAA findings combined with positive αN results but not with negative αN results. Further investigation into the association of dysregulated glycemic control with humoral immunity to natural infection is warranted, given the well-documented increase in incidence in type 1 and type 2 diabetes following COVID-19. Prior positive NAA results were also associated with a few nonspecific abnormalities of the complete blood cell count.

Introduction: Early identification of whether bloodstream infections (BSIs) are caused by gram-negative or gram-positive bacteria is crucial for initiating timely and appropriate antibiotic treatment. This study aimed to investigate potential laboratory markers for predicting the type of bacterial infection in patients with suspected BSI.

Methods: Patients who presented at the emergency department with positive blood cultures were included in this study. Clinical and laboratory data collected within the first 24 hours of admission were analyzed.

Results: The study included 338 patients. Clinically significant differences in platelet count and procalcitonin (PCT) level were observed between patients with gram-positive and gram-negative infections. Platelet counts and PCT levels as predictors of infection were relatively ineffective, however, with receiver operating characteristic (ROC) area under the curve (AUC) values of 0.63 and 0.66, respectively. Subsequently, a specific cluster of patients characterized by normal to high platelet counts (170-318 ×109/L) and mildly elevated PCT levels (0-31.06 ng/mL) was identified using k means clustering. In this cluster, platelet counts of 284 ×109/L or higher combined with PCT levels of 2.73 ng/mL or less demonstrated a sensitivity of 70.3%, a specificity of 78.9%, and ROC AUC values of 0.82 for predicting gram-positive bacterial infections.

Discussion: The combined use of platelet count and PCT level could predict gram-positive bacterial infections in specific populations. This study may provide a practical strategy for the rapid identification of bacterial groups in patients with suspected BSI.

Introduction: Fentanyl, a highly potent synthetic opioid, has contributed to a rapid rise in opioid-related overdoses and fatalities nationwide. Consequently, the need for accurate and timely testing for fentanyl has become critical. Immunoassay screens, reported as presumptive positive or negative, help address this need. We sought to compare the clinical performance of 2 US Food and Drug Administration (FDA)-approved fentanyl immunoassays-the Thermo Scientific DRI Fentanyl II Drugs of Abuse Assay and the Lin-Zhi International LZI Fentanyl (Q) Enzyme Immunoassay-for detection of fentanyl and its metabolites in urine, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the reference method.

Methods: A total of 806 urine specimens were screened using 2 FDA-approved fentanyl immunoassays on Beckman Coulter DxC 700 AU Chemistry Analyzer. Of these specimens, 183 that were both positive and negative by immunoassay were further analyzed by LC-MS/MS for the presence or absence of fentanyl, norfentanyl, and 4-anilino-N-phenethylpiperidine (4-ANPP).

Results: Of the 806 specimens, 786 (98%) provided concordant results and 20 (2%) had discordant results between the 2 immunoassays. Concordance between immunoassays and LC-MS/MS was 97% for the LZI assay and 89% for the DRI assay. Among the 183 specimens tested, 4-ANPP was detected in 13 (7%).

Discussion: The 2 assays demonstrated comparable clinical utility for incorporation into a urine drug screen panel.

Introduction: Hepatocellular carcinoma (HCC) diagnosis requires a combination of elevated ɑ-fetoprotein (AFP) levels and liver imaging. We evaluated the role of prothrombin induced by vitamin K antagonist-II (PIVKA-II) in patients with suspected HCC.

Methods: A retrospective analysis was conducted on adult Indian patients with suspected HCC who had elevated AFP and PIVKA-II levels and had undergone radiologic investigation.

Results: Among 178 suspected cases, 144 (80.99%) were diagnosed with HCC; the median age of these 144 patients was 62 years (IQR, 54-68 years). The median AFP and PIVKA-II levels were 14.68 ng/mL (IQR, 3.83-146.50 ng/mL) and 354.50 ng/mL (IQR, 49.41-4293.40 ng/mL), respectively. The sensitivity and specificity were 52.08% and 88.24% for AFP (≥10 ng/mL) and 80.56% and 32.35% for PIVKA-II (≥40 ng/mL). The false positivity rate of PIVKA-II was 67.60%. PIVKA-II showed moderate correlation (r = 0.413) with HCC size and was more reliable than AFP for HCC lesions larger than 5 cm (area under the curve = 0.731 vs 0.627). PIVKA-II levels were lower following therapy for HCC (682.98-122.50 ng/mL; P < .001) than AFP levels (15.05-6.50 ng/mL; P = .30). Among AFP-negative patients with HCC, 68.10% had elevated PIVKA-II levels.

Discussion: With its higher false positivity rate, PIVKA-II may not be a reliable marker for HCC, although it may be useful in larger HCC lesions and in AFP-negative patients. Establishing a newer cutoff value for PIVKA-II among the Indian population may improve its specificity in the diagnosis and management of HCC.

Introduction: Congenital hypofibrinogenemia is a genetic disorder caused by defects in the fibrinogen gene. We identified a case of congenital hypofibrinogenemia with mutations in the FGA, FGB, and FGG genes associated with bleeding risk and conducted experimental studies to explore the condition's pathogenesis.

Methods: To investigate the bleeding risk in the proband, we performed coagulation screening and genetic analysis, supplemented by sodium dodecyl sulfate polyacrylamide gel electrophoresis, electron microscopy, sequence conservation analysis, and thromboelastography to elucidate the pathogenic mechanism.

Results: Fibrinogen levels in the proband's plasma were measured by 3 methods: 0.81 g/L (Clauss assay), 0.95 g/L (prothrombin time derived), and 0.87 g/L (enzyme-linked immunosorbent assay). The proband and her father had c.37T > C (p.Tyr13His) in the FGG gene; c.959-16_959-13delTTTG deletion mutation, c.567C > T (p.Ser189=), c.1125C > T (p.Tyr375=), c.1433G > A (p.Arg478Lys), and c.1433G > A (p.Arg478Lys) in the FGB gene; and c.991A > G (p.Thr331Ala) in the FGA gene. Scanning electron microscope analysis showed that the proband's fibrin fibers were fine, with a loose spatial structure and increased pore size.

Discussion: The c.959-16_959-13delTTTG deletion is the main cause of congenital hypofibrinogenemia in this family. The γTyr13His heterozygous mutation may have a minor impact on the structure and function of the fibrinogen molecule. The Bβ(Ser189=, Tyr375=, Arg478Lys) and AαThr331Ala mutations may have a certain impact on the proband's clinical phenotype.

Introduction: Rapid and accurate identification of pathogens is essential for managing lung infections in patients following kidney transplantation. This study aimed to compare the diagnostic performance and clinical utility of conventional detection methods and metagenomic next-generation sequencing (NGS) in kidney transplant recipients with respiratory infections.

Methods: We conducted a retrospective analysis of metagenomic NGS and conventional detection method results in 71 patients, examining the spectrum of pathogen detection characteristics between the 2 methods.

Results: The overall positivity rate of conventional detection methods was statistically significantly lower than that of metagenomic NGS (61.97% vs 84.51%, P = .004). Among the 38 participants who tested positive by both methods, metagenomic NGS identified a greater number of pathogens than conventional detection methods. Following metagenomic NGS results, antibiotic therapy was modified in 71.83% of participants, leading to improved prognoses in 33.33% of patients. In additionally, metagenomic NGS demonstrated a shorter turnaround time than conventional detection methods. The most prevalent bacteria identified in pulmonary infections among kidney transplant recipients were Klebsiella pneumoniae, while cytomegalovirus was the most common virus and Pneumocystis jirovecii was the predominant fungus.

Discussion: This study offers preliminary insights into the spectrum of pathogens responsible for pulmonary infections following kidney transplantation, laying the foundation for better understanding their clinical characteristics. In patients with post-transplant pulmonary infections, metagenomic NGS outperforms conventional detection methods in terms of pathogen detection, speed, positivity rate, sensitivity, and ability to diagnose mixed infections.

The American Society for Clinical Pathology Board of Certification Research and Development Committee has undertaken regular surveys of Medical Laboratory Science (MLS) education programs. Results of previous surveys were reported in 2019 and 2022. The purpose of these recurring surveys is to support MLS programs in their educational mission by providing information about current issues and trends that may affect program resources and MLS education, including data for grant applications, funding requests, and strategic planning. Program-related topics covered in the surveys included program director and faculty education and certification requirements, program structure and duration, student grade point averages and acceptance data, clinical site numbers and status, and faculty numbers and vacancies.

Introduction: Patients with rheumatoid arthritis (RA) can develop interstitial lung disease (ILD) with increased morbidity and mortality. The diagnostic values of serum carcinoembryonic antigen (CEA), cancer antigen (CA) 125, and human epididymis protein 4 (HE4) in these patients was unclear.

Methods: A cross-sectional study enrolled patients with RA and healthy control individuals from January 2020 to August 2024. Demographics, disease duration, high-resolution computed tomography scan images, and laboratory test results were collected and analyzed.

Results: The cohort comprised 87 patients with RA (40 with and 47 without ILD) and 82 healthy individuals. Serum CEA, CA125, and HE4 levels were clinically significantly higher in patients with RA than in healthy control individuals; they were also elevated in patients with RA and ILD compared with patients with RA but not ILD. Increased levels of CEA, CA125, and HE4 were associated with more severe impairments in pulmonary function. Each biomarker demonstrated satisfactory performance, with the combination of all 3 yielding the highest efficacy (sensitivity = 95.00%, specificity = 95.74%, area under the curve = 0.993) for evaluating ILD.

Discussion: Serum CEA, CA125, and HE4 levels were clinically significantly elevated in patients with RA, particularly in those patients with ILD, and higher levels correlated with poorer pulmonary function. Their combination could facilitate accurate assessment of RA-associated ILD.