Background: Twenty-four-hour urine collection remains the reference method for quantitative urinary biomarker assessment, yet its clinical utility is limited by logistical challenges and suboptimal patient adherence. Morning spot urine offers a practical alternative, but its agreement with 24-hour excretion- particularly across a broad panel of analytes-remains to be systematically evaluated. The aim of this study is to establish reference intervals for routine urinary biochemical parameters in 24-hour, first-morning, and random urine samples from a healthy Chinese adult population, and to evaluate the concordance of creatinine-adjusted values between first-morning urine and 24-hour urine collections for their potential use as a reliable alternative. Methods: We enrolled 230 healthy adults (115 males and 115 females; age range, 20-50 years) following the Clinical and Laboratory Standards Institute (CLSI) EP28-A3c guidelines. Participants provided morning, random, and complete 24-hour urine specimens. Fifteen biochemical parameters-glucose (GLU), creatinine (CREA), uric acid (UA), urea, microalbumin (mALB), retinol-binding protein (RBP), 82-microglobulin (82-MG), total protein (TP), alpha-amylase (alpha-AMY), and electrolytes (Na+, K+, Cl-, Ca2+, Mg2+, and P)-were quantified on a BS-2800M analyzer (Mindray Bio-Medical Electronics Co., Ltd.). Reference intervals were established for each specimen type, both with and without creatinine normalization. Gender differences were assessed via the Mann-Whitney test, and correlations between specimen types were evaluated via Spearman rank correlation. Results: Prior to creatinine correction, CREA, UA, and Ca2(+) exhibited significant gender differences (P<0.05), warranting sex-specific reference limits. After adjustment for CREA, only the albumin-to-creatinine ratio (ACR) remained significantly different between the genders. While the absolute concentrations differed markedly between 24-hour and spot samples, CREA normalization substantially improved concordance: six analytes (GLU, K+, TP, UA, urea, and alpha-AMY) showed >50% increases in correlation coefficients with 24-hour excretion when CREA-corrected morning urine was used. Conclusions: CREA-adjusted morning urine demonstrated strong analytical agreement with 24-hour collections for multiple clinically relevant biomarkers. Our data support its use as a reliable, patient-friendly surrogate in routine clinical chemistry, particularly when 24-hour collection is impractical. The reported reference intervals-stratified by sex and specimen type-provide a robust foundation for laboratory implementation.
Background: Vacuum blood collection tubes are essential for clinical testing, but traditional tubes have a number of limitations. Microtubes are increasingly being used to reduce required blood volumes and patient discomfort. Further research needs to be conducted on the efficacy of low-volume blood collection tubes in clinical laboratories. This study aimed to analyze the consistency of coagulation test results obtained using Gongdong and Kangjian microtubes. Methods: In total, 50 randomly selected patients underwent coagulation tests at our hospital using Yangpu coagulation tubes, Kangjian microtubes, and Gongdong microtubes. A CX-9000 blood coagulation analyzer was employed to determine the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (FIB) level, D-dimer level, fibrinogen degradation product (FDP) level, and antithrombin III (AT-III) level. Additionally, linear fitting was performed with the control tube results as "X" and the inspection tube results as "Y". The expected bias (Bx) was then calculated using the following formula: Bx = a + (b - 1) / Xc, where Xc represents the medical level. Finally, the consistency between the results from the Yangpu coagulation tubes and microtubes, as well as the consistency between the results from the Gongdong and Kangjian microtubes, was assessed using 1/2 Clinical Laboratory Improvement Amendments (CLIA)'88 as the criterion. Results: No statistically significant differences were observed between the Yangpu tubes and both types of microtubes (P>0.05). Moreover, a strong correlation was found between the coagulation test results for the Yangpu coagulation blood tubes and those for the microtubes (P<0.05). In addition, the APTT, PT, TT, FIB, D-dimer, FDP, and AT-III results between the Kangjian and Gongdong microtubes were highly correlated and met the specification requirements. Conclusions: While this study demonstrates strong analytical agreement between conventional tubes and microtubes, further clinical studies are warranted to validate these findings in diverse patient cohorts and to assess the impact of tube substitution on clinical outcomes.
Background: The triglyceride-glucose (TyG) index, a reliable surrogate for insulin resistance, reflects cardiometabolic status and correlates with coronary artery disease (CAD) progression. Myocardial infarction (MI)-CAD's most severe acute manifestation with high morbidity and mortality-is critical for CAD risk stratification. While the TyG index is linked to CAD in specific subgroups, its association with MI clinical characteristics in unselected CAD cohorts remains unclear. This study investigates this relationship in a large cohort, adjusts for confounders, and verifies consistency via subgroup analyses, providing etiological clues for their potential link and informing CAD management. Methods: A total of 5,001 patients that had been diagnosed with CAD between September 2018 and September 2021 at Jiangnan University Medical Center and Jiangsu Provincial Hospital were recruited into this study. Medical record data, treatment regimens, and clinical outcomes of these patients were collected for a cross-sectional study analysis. Patients were stratified into four groups based on the quartile levels of their TyG index: Q1 (n=1,254, TyG index <= 8.31), Q2 (n=1,243, 8.31< TyG index <= 8.69), Q3 (n=1,256, 8.69< TyG index <= 9.15), and Q4 (n=1,248, TyG index >9.15). Multivariate logistic regression analysis was performed to explore the association between the TyG index and clinical characteristics of MI in patients with CAD. Results: In a multivariate logistic regression analysis of 5,001 patients with CAD, the results showed that with the increase in TyG index, the strength of the association between the TyG index and diagnosis of MI in CAD patients gradually increased compared with patients with angina pectoris [Q2: odds ratio (OR) =1.31, 95% confidence interval (CI): 1.07-1.60; Q3: OR =1.39, 95% CI: 1.13-1.71; Q4: OR =1.72, 95% CI: 1.38-2.15; P<0.001] after adjusting for potential confounders including age, sex, and other significant covariates. Subgroup analyses further validated this relationship across multiple stratification variables (prior percutaneous coronary intervention (PCI), history of hypertension, systolic blood pressure (SBP), body mass index (BMI), smoking status, sex and age), with all subgroups showing statistically significant correlations. Conclusions: Elevated TyG index in coronary heart disease patients showed significant correlation with clinical characteristics of MI. This finding provides aetiological clues for a potential causal relationship between TyG index and MI.
Background: Alkaline phosphatase (ALP) is a key biomarker of hepatobiliary and skeletal disease. Isolated elevations often prompt extensive investigations to rule out various pathologies, which can be invasive and to the detriment of the patient's physical, financial, and emotional well-being. One benign diagnosis of exclusion for an isolated elevated ALP value is macro-ALP, an immunoglobulin-bound enzyme complex. However, very little literature exists describing this phenomenon, which may prevent its recognition by clinicians and laboratory directors. Additionally, macro-ALP can be difficult to distinguish from other pathologic etiologies, as standard colorimetric assays can only detect the quantity, but not the size, of the ALP enzyme. Case Description: A 48-year-old male with a history of hypothyroidism and erectile dysfunction demonstrated a persistent 3-year discrepancy in ALP values between our in-house dry chemistry platform (Vitros 7600, QuidelOrtho, microslide technique) and an outside laboratory wet chemistry assay (ARUP Laboratories, Roche Cobas 8000). In-house results were normal (63-91 U/L; reference range, 34-122 U/L), while outside laboratory testing showed persistent elevations (173-242 U/L; reference range, 40-120 U/L). Other markers were normal. Following evaluation by endocrinology and gastroenterology with no concrete diagnosis, our laboratory elected to perform a polyethylene glycol (PEG) precipitation test (Abbott Alinity CI), which confirmed macro-ALP (<40% recovery). The patient remained asymptomatic, and no pathology was identified. Conclusions: Macro-ALP is a rare cause of isolated ALP elevation. This case highlights a benign presentation in a healthy individual and underscores how methodological differences between wet and dry chemistry assays can yield discrepant results. Awareness of this benign variant and assay-dependent variability can prevent unnecessary investigations.
Background: Comprehensive iron status and erythropoiesis evaluation requires a combination of reliable tests and clinical indicators. Current diagnostic tools for these evaluations have key limitations that justify the exploration of mean reticulocyte volume (MRV) alongside or in combination with other reticulocyte indices. Mindray BC-6800 Plus (TM) counter reports MRV. We study its values in anemia of different underlying causes, the reliability for the diagnosis of iron deficient erythropoiesis (IDE), and its trend in response to therapy. Methods: Precision was assessed by repeated analysis; stability was tested by re-measuring samples after 0, 8, and 24 hours of store. A prospective study was conducted during 4 months. The study group included 553 consecutive patients, 196 non-anemic (105 were considered healthy and 91 latent iron deficiency), the 357 anemic patients (135 microcytic, 145 normocytic and 77 macrocytic). A total of 189 patients at diagnosis of anemia were studied at a second follow-up visit, with MRV reassessed after oral or intravenous (IV) iron supplementation at the specified intervals, to verify the change in MRV after therapy. Differences among groups were assessed using analysis of variance, with significance at P<0.05. Receiver operating characteristic analysis was used to assess the diagnostic performance of MRV for detecting IDE, and the gold standard was soluble transferrin receptor (sTfR) >52 nmol/L. A validation group of 150 consecutive patients, collected in a separate period and with similar inclusion criteria, served to confirm findings. The recruitment period was November 2024-January 2025 (study group) and February 2025 (validation group) in Hospital Galdakao Usansolo. Results: Coefficients of variation (CVs) of MRV measurements were <1.0%, MRV was stable within 8 hours. By using a cut-off of 94.6 fL, IDE can be diagnosed with a sensitivity of 82.9% and a specificity of 97.6%. The area under the curve was 0.929 [95% confidence interval (CI): 0.889-0.949]. Four weeks after oral iron therapy MRV showed an average increase of 4.5%; when the selected therapy was IV iron the average increment was 8.2% within 1 week, P<0.001. Conclusions: MRV is a reliable marker to identify IDE, useful not only for a real-time evaluation of erythropoiesis also to verify the effectiveness of iron replacement. MRV may allow the early detection of iron deficiency, facilitating timely diagnosis and management of the disease.
