Evaluation of Cellular Responses to ChAdOx1-nCoV-19 and BNT162b2 Vaccinations

While numerous studies have evaluated humoral responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, data on the cellular responses to these vaccines remain sparse. We evaluated T cell responses to ChAdOx1-nCoV-19 and BNT162b2 vaccinations using an interferon gamma (IFN-γ) release assay (IGRA). ChAdOx1-nCoV-19- and BNT162b2-vaccinated participants initially showed stronger T cell responses than unvaccinated controls. The T cell response decreased over time and increased substantially after the administration of a BNT162b2 booster dose. Changes in the T cell response were less significant than those in the anti-receptor-binding domain IgG antibody titer. The study results can serve as baseline data for T cell responses after SARS-CoV-2 vaccination and suggest that the IGRA can be useful in monitoring immunogenicity.

Evaluation of Seroprevalence of SARS-CoV-2 IgG in Healthcare Workers in a Tertiary Hospital in Seoul / 대한임상미생물학회지

Healthcare workers (HCWs) may be at high risk for exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of their frequent contact with patients or the direct handling of respiratory samples. We investigated the seroprevalence of SARS-CoV-2 IgG in HCWs in Seoul compared to those in coronavirus disease (COVID-19) patients and community-based individuals to evaluate the antibody response. A total of 358 samples from 348 individuals (155 HCWs, 7 COVID-19 patients, and 186 community-based individuals) were collected from April to November 2020. SARS-CoV-2 IgG was detected in 1 of 155 HCWs (1 of 46 HCWs with direct contact), 7 of 7 COVID-19 patients, and none of the 186 communitybased individuals (95% CI: 0.6%, 0.1 - 3.6%; 100%, 64.5 - 100%; 0.0%, 0.0 - 2.0%, respectively).The single HCW with a positive result showed 2.32 signal-to-cutoff (S/C) and 2.31 S/C at a 3-week interval. Therefore, it was assumed to be a false positive due to autoantibody or medication. The positive samples from 7 patients had a median of 3.79 S/C (range 1.72 - 6.54). The seroprevalence of SARS-CoV-2 IgG in HCWs was very low. The current infection control standard seems to be effective in protecting HCWs from COVID-19.

Evaluation of Seroprevalence of SARS-CoV-2 IgG in Healthcare Workers in a Tertiary Hospital in Seoul / 대한임상미생물학회지

Healthcare workers (HCWs) may be at high risk for exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of their frequent contact with patients or the direct handling of respiratory samples. We investigated the seroprevalence of SARS-CoV-2 IgG in HCWs in Seoul compared to those in coronavirus disease (COVID-19) patients and community-based individuals to evaluate the antibody response. A total of 358 samples from 348 individuals (155 HCWs, 7 COVID-19 patients, and 186 community-based individuals) were collected from April to November 2020. SARS-CoV-2 IgG was detected in 1 of 155 HCWs (1 of 46 HCWs with direct contact), 7 of 7 COVID-19 patients, and none of the 186 communitybased individuals (95% CI: 0.6%, 0.1 - 3.6%; 100%, 64.5 - 100%; 0.0%, 0.0 - 2.0%, respectively).The single HCW with a positive result showed 2.32 signal-to-cutoff (S/C) and 2.31 S/C at a 3-week interval. Therefore, it was assumed to be a false positive due to autoantibody or medication. The positive samples from 7 patients had a median of 3.79 S/C (range 1.72 - 6.54). The seroprevalence of SARS-CoV-2 IgG in HCWs was very low. The current infection control standard seems to be effective in protecting HCWs from COVID-19.

Effectiveness of Plasma and Urine Neutrophil Gelatinase-Associated Lipocalin for Predicting Acute Kidney Injury in High-Risk Patients

Background@#Neutrophil gelatinase-associated lipocalin (NGAL) is a useful biomarker for acute kidney injury (AKI) prediction. However, studies on whether using both plasma NGAL (PNGAL) and urine NGAL (UNGAL) can improve AKI prediction are limited. We investigated the best approach to predict AKI in high-risk patients when using PNGAL and UNGAL together. @*Methods@#We enrolled 151 AKI suspected patients with one or more AKI risk factors. We assessed the diagnostic performance of PNGAL and UNGAL for predicting AKI according to chronic kidney disease (CKD) status by determining the areas under the receiver operating curve (AuROC). Independent predictors of AKI were assessed using univariate and multivariate logistic regression analyses. @*Results@#In the multivariate logistic regression analysis for all patients (N = 151), Model 2 and 3, including PNGAL (P = 0.012) with initial serum creatinine (S-Cr), showed a better AKI prediction power (R2 = 0.435, both) than Model 0, including S-Cr only (R2 = 0.390). In the non-CKD group (N = 135), the AuROC of PNGAL for AKI prediction was larger than that of UNGAL (0.79 vs 0.66, P = 0.010), whereas in the CKD group (N = 16), the opposite was true (0.94 vs 0.76, P = 0.049). @*Conclusions@#PNGAL may serve as a useful biomarker for AKI prediction in high-risk patients. However, UNGAL predicted AKI better than PNGAL in CKD patients. Our findings provide guidance for selecting appropriate specimens for NGAL testing according to the presence of CKD in AKI high-risk patients.

Report of the Korean Association of ExternalQuality Assessment Service on AutoimmuneTesting (2018–2019)

Under the Korean Association of External Quality Assessment Service,autoimmune proficiency testings (PT) for six test items were performed in2018–2019 for laboratory quality improvement. We conducted two trials peryear and sent three PT materials for anti-nuclear antibody (ANA) testing andtwo PT materials for anti-mitochondrial antibody (AMA), anti-smooth muscleantibody (SMA), anti-thyroglobulin antibody (anti-Tg), anti-thyroperoxidaseantibody (anti-TPO), and anti-double stranded DNA antibody (anti-dsDNA)testing in each trial. The analysis was conducted based on the informationand results of each test item entered by the laboratory. The report comprisedof a common report that showed the characteristics of all the participatinglaboratories and a laboratory-specific report that showed the assessmentdata of individual laboratories. The intended response rates for ANA, AMA,SMA, and anti-dsDNA qualitative tests were over 97.5%, 88.2%, 85.0%, and90.4%, respectively. The coefficient of variations for anti-Tg and anti-TPO was10.4%–70.1% and 16.6%–21.0%, respectively. The number of participatinglaboratories in 2019 was more than that in 2018. We believe this statisticalreport will be useful to interpret external PT results and set up autoimmuneassays at each laboratory.

A Case of Peritonitis and Disseminated Mucormycosis Caused by Mucor circinelloides in a Patient with Nodal Marginal Zone B-cell Lymphoma

Mucormycosis is a fungal infection, which is difficult to treat due to its rapid dissemination and low susceptibility to anti-fungal agents. Peritonitis preceded by gastrointestinal mucormycosis is very rare, and only a few cases have been reported. We present a case of peritonitis and disseminated mucormycosis caused by Mucor circinelloides in an immunocompromised patient. A 59-year-old man, diagnosed with nodal marginal zone B-cell lymphoma, was diagnosed with liver failure due to severe septic shock. A white, woolly cotton-like growth, which was consistent with that of Mucor species, was isolated from ascites and sputum specimens. Targeted DNA sequencing confirmed the isolate as M. circinelloides with 100% identity. Despite anti-fungal treatment, the patient died after four days. This is a rare case of peritonitis and disseminated mucormycosis that was probably preceded by gastrointestinal mucormycosis caused by M. circinelloides, as determined by molecular methods. Accurate and rapid identification of mold using molecular methods might be necessary for early treatment in critical cases, and more cases should be clinically evaluated further.

Clinical Utility of Fecal Neutrophil Gelatinase-Associated Lipocalin and Calprotectin as Biomarkers of Clostridioides (Clostridium) difficile Infection

Background@#Current methods for diagnosing Clostridioides difficile infections (CDIs) fail to provide information on their severity. Fecal neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin are candidate biomarkers for evaluating the severity of intestinal inflammation. We assessed fecal NGAL and calprotectin levels in patients with CDI and compared these values between subgroups of patients. We also evaluated their utility in predicting CDI clinical outcomes. @*Methods@#A total of 147 leftover fecal samples were obtained; 97 samples were from patients with CDI and 50 were from routine healthcare checkups. Fecal calprotectin and NGAL levels were measured using a Quantitative Fecal NGAL ELISA Kit and Quantitative Fecal Calprotectin ELISA Kit (Epitope Diagnostics, USA). @*Results@#Significant differences in fecal NGAL and calprotectin levels were observed between CDI patients and healthy controls (P<0.0001 for both). Significant differences in fecal NGAL and calprotectin levels were also seen between patients with high and low tcdB gene load (P=0.005 and 0.006, respectively). Fecal calprotectin levels were lower in patients with leukopenia (P=0.002), and high calprotectin levels were associated with severe CDI and treatment failure (P=0.021 and 0.033, respectively). @*Conclusions@#Fecal NGAL and calprotectin levels were higher in patients with CDI than in healthy controls and correlated with high tcdB gene loads. Leukopenia patients with CDI had significantly lower levels of calprotectin and the assessment should be regarded with caution. High fecal calprotectin levels were also associated with severe CDI and treatment failure. This warrants future studies with more patients and in-depth analyses.

Performance Evaluation of the QXDx BCR-ABL %IS Droplet Digital PCR Assay

Accurate detection of BCR-ABL fusion transcripts at and below molecular response (MR) 4 (0.01% International Scale [IS]) is required for disease monitoring in patients with chronic myeloid leukemia (CML). We evaluated the analytical performance of the QXDx BCR-ABL %IS (Bio-Rad, Hercules, CA, USA) droplet digital PCR (ddPCR) assay, which is the first commercially available ddPCR-based in vitro diagnostics product. In precision analysis, the %CV was 9.3% and 3.0%, with mean values of 0.031% IS and 9.4% IS, respectively. The assay was linear in the first order, ranging from 0.032% IS to 20% IS. The manufacturer-claimed limit of blank, limit of detection, and limit of quantification were verified successfully. There was a very strong correlation between the results of the QXDx BCR-ABL %IS ddPCR assay and the ipsogen BCR-ABL1 Mbcr IS-MMR (Qiagen, Hilden, Germany) real-time quantitative PCR assay (r=0.996). In conclusion, the QXDx BCR-ABL %IS ddPCR assay can provide reliable results for CML patients.

First Case in Korea of Group B Streptococcus With Reduced Penicillin Susceptibility Harboring Amino Acid Substitutions in Penicillin-Binding Protein 2X

No abstract available.

Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

BACKGROUND: Several factors contribute to differences in Streptococcus pneumoniae serotype distribution. We investigated the serotype distribution and antimicrobial resistance of S. pneumoniae isolated between 2014 and 2016 in Korea. METHODS: We collected a total of 1,855 S. pneumoniae isolates from 44 hospitals between May 2014 and May 2016, and analyzed the serotypes by sequential multiplex PCR. We investigated the distribution of each serotype by patient age, source of the clinical specimen, and antimicrobial resistance pattern. RESULTS: The most common serotypes were 11A (10.1%), followed by 19A (8.8%), 3 (8.5%), 34 (8.1%), 23A (7.3%), and 35B (6.2%). The major invasive serotypes were 3 (12.6%), 19A (7.8%), 34 (7.8%), 10A (6.8%), and 11A (6.8%). Serotypes 10A, 15B, 19A, and 12F were more common in patients ≤5 years old, while serotype 3 was more common in patients ≥65 years old compared with the other age groups. The coverage rates of pneumococcal conjugate vaccine (PCV)7, PCV10, PCV13, and pneumococcal polysaccharide vaccine 23 were 11.8%, 12.12%, 33.3%, and 53.6%, respectively. Of the 1,855 isolates, 857 (46.2%) were multi-drug resistant (MDR), with serotypes 11A and 19A predominant among the MDR strains. The resistance rates against penicillin, cefotaxime, and levofloxacin were 22.8%, 12.5%, and 9.4%, respectively. CONCLUSIONS: There were significant changes in the major S. pneumoniae serotypes in the community. Non-PCV13 serotypes increased in patients ≤5 years old following the introduction of national immunization programs with the 10- and 13-polyvalent vaccines.

Acute myocarditis associated with non-typhoidal Salmonella gastroenteritis

Acute myocarditis is clinically rare in children, but poses a significant risk for morbidity and mortality. Children with myocarditis show a wide variety of clinical manifestations ranging from subclinical myocarditis to heart failure, hemodynamic compromise, arrhythmia, and even sudden death. Salmonella species are associated with clinical presentations including gastroenteritis, enteric fever, bacteremia, and extra-intestinal focal infections. Non-typhoidal Salmonella infections usually cause self-limiting gastroenteritis, but are rarely associated with myocarditis. In this report, we present a case of myocarditis associated with Salmonella serogroup B gastroenteritis in a previously healthy 15-year-old boy.

Usefulness of Enhanced Liver Fibrosis, Glycosylation Isomer of Mac-2 Binding Protein, Galectin-3, and Soluble Suppression of Tumorigenicity 2 for Assessing Liver Fibrosis in Chronic Liver Diseases

BACKGROUND: Liver biopsies have been partially replaced by noninvasive methods for assessing liver fibrosis. We explored the usefulness of four novel biomarkers, enhanced liver fibrosis (ELF), glycosylation isomer of Mac-2 binding protein (M2BPGi), galectin-3, and soluble suppression of tumorigenicity 2 (sST2), in association with liver fibrosis. METHODS: ELF, M2BPGi, galectin-3, and sST2 were assayed in 173 patients with chronic liver diseases. The results were analyzed according to fibrosis grade (F0/1, F2, and F3/4) by transient elastography (TE). RESULTS: ELF, M2BPGi, galectin-3, and sST2 values differed significantly according to TE grade; ELF and M2BPGi values were higher in F2 and F3/4 than in F0/1 (P≤0.001, all), sST2 values were higher in F3/4 than in F0/1 and F2 (P < 0.05), and galectin-3 values were higher in F3/4 than in F0/1 (P=0.0036). ELF and M2BPGi showed good TE fibrosis detection performance (area under the curves [AUC], 0.841 and 0.833 for ≥F2; and 0.837 and 0.808 for ≥F3). The sensitivity and specificity for predicting TE grade F≥2 were 84.1% and 76.7% for ELF and 63.6% and 91.5% for M2BPGi. CONCLUSIONS: This is the first study to compare the liver fibrosis assessment of four novel biomarkers: ELF, M2BPGi, galectin-3, and sST2. The biomarkers varied significantly according to TE grade, and each biomarker showed a different trend. ELF and M2BPGi seem to have comparable good performance for detecting liver fibrosis.

Characteristics of Helicobacter pylori-seropositive subjects according to the stool antigen test findings: a prospective study

BACKGROUND/AIMS: In countries with a higher risk of gastric atrophic gastritis, noninvasive tests are helpful for a more reliable diagnosis of Helicobacter pylori infection. The aim of this study was to evaluate the characteristics of seropositive subjects according to their stool H. pylori antigen test, serum pepsinogen (PG) assay, and endoscopic findings. METHODS: Consecutive subjects who visited Konkuk University Medical Center for upper gastrointestinal endoscopy for a regular check-up were included in a prospective setting if the serum anti-H. pylori immunoglobulin G assay was positive. A H. pylori antigen stool test was measured using a stool H. pylori antigen enzyme-linked immunosorbent assay kit on the same day as a serum PG assay and endoscopy. RESULTS: Of 318 seropositive subjects, 256 (80.5%) showed positive stool test findings. Subjects with a negative stool test result showed lower serum PG I (p < 0.001) and PG II (p < 0.001) levels and higher PG I/II ratio (p < 0.001) than those with a positive stool test. Chronic atrophic gastritis was more common in the positive stool test group than the negative stool test group on endoscopic finding (p = 0.009). A higher serum PG I level (p = 0.001) and a lower serum PG I/II ratio (p = 0.001) were independent risk factors for the presence of H. pylori antigen in stool. CONCLUSIONS: A high serum PG level denotes an ongoing current H. pylori infection with positive stool H. pylori antigen test findings. Seropositive subjects with increased gastric secreting ability tend to have H. pylori in their fecal material as reflected by a positive stool H. pylori antigen test finding.

Automated Nucleic Acid Extraction Systems for Detecting Cytomegalovirus and Epstein-Barr Virus Using Real-Time PCR: A Comparison Study Between the QIAsymphony RGQ and QIAcube Systems

BACKGROUND: Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are increasingly important in immunocompromised patients. Nucleic acid extraction methods could affect the results of viral nucleic acid amplification tests. We compared two automated nucleic acid extraction systems for detecting CMV and EBV using real-time PCR assays. METHODS: One hundred and fifty-three whole blood (WB) samples were tested for CMV detection, and 117 WB samples were tested for EBV detection. Viral nucleic acid was extracted in parallel by using QIAsymphony RGQ and QIAcube (Qiagen GmbH, Germany), and real-time PCR assays for CMV and EBV were performed with a Rotor-Gene Q real-time PCR cycler (Qiagen). Detection rates for CMV and EBV were compared, and agreements between the two systems were analyzed. RESULTS: The detection rate of CMV and EBV differed significantly between the QIAsymphony RGQ and QIAcube systems (CMV, 59.5% [91/153] vs 43.8% [67/153], P=0.0005; EBV, 59.0% [69/117] vs 42.7% [50/117], P=0.0008). The two systems showed moderate agreement for CMV and EBV detection (kappa=0.43 and 0.52, respectively). QIAsymphony RGQ showed a negligible correlation with QIAcube for quantitative EBV detection. QIAcube exhibited EBV PCR inhibition in 23.9% (28/117) of samples. CONCLUSIONS: Automated nucleic acid extraction systems have different performances and significantly affect the detection of viral pathogens. The QIAsymphony RGQ system appears to be superior to the QIAcube system for detecting CMV and EBV. A suitable sample preparation system should be considered for optimized nucleic acid amplification in clinical laboratories.

Performance Evaluation of Cartridge-Type Blood Gas Analyzer: i-Smart 300

BACKGROUND: Blood gas analysis plays a crucial role in critical care settings, and immediate and precise analysis improves clinical outcomes through prompt treatment. We evaluated the performance of a cartridge-type blood gas analyzer, i-Smart 300 (i-SENS, Korea), according to the Clinical and Laboratory Standard Institute (CLSI) guidelines and compared it to a conventional blood gas analyzer. METHODS: The precision was evaluated according to CLSI EP5-A3. The i-Smart 300 was compared to the Stat Profile Critical Care Xpress (STP CCX) (Nova CCX; Nova Biomedical, USA) according to CLSI EP9-A3 using the following eight parameters: pH, partial carbon dioxide pressure, partial oxygen pressure, sodium, potassium, chloride, ionized calcium, and hematocrit. Linearity was determined using five levels of control materials according to CLSI EP6-A. RESULTS: Within-run precision and total precision, demonstrated as coefficients of variation, ranged from 0.02 to 2.50% and from 0.05 to 3.46%, respectively. Correlation analysis yielded a correlation coefficient from 0.966 to 0.996 between the i-Smart 300 and the conventional analyzer (Nova CCX). The i-Smart 300 showed excellent linearity at eight parameters with acceptable percent recovery. CONCLUSIONS: The i-Smart 300, a portable cartridge-type blood gas analyzer, showed high precision and good correlation with a traditional bench-top blood gas analyzer. It could be useful in critical care settings.

Performance Evaluation of the JEOL BioMajesty JCA-BM6010/C Automated Clinical Chemistry Analyzer

BACKGROUND: JEOL BioMajesty JCA-BM6010/C (JCA-BM6010/C, JEOL Ltd., Japan) is a recently developed ultra-compact automated clinical chemistry analyzer with a throughput of 1,200 tests per hour. Here, we present the first performance evaluation of JCA-BM6010/C. METHODS: We evaluated the precision, linearity, correlation, accuracy, and carryover of 11 analytes (ALP, ALT, AST, calcium, creatinine, GGT, glucose, LDH, total bilirubin, total protein, and uric acid) using the JEOL closed reagent (JEOL Ltd.) according to the guidelines of the Clinical Laboratory Standards Institute. Linearity was further evaluated for ALT, AST, and GGT using open reagents by Sekisui (Japan). The performance of JCA-BM6010/C was compared to that of the Roche-Hitachi Cobas 8000 c702 chemistry autoanalyzer (Cobas 8000, Roche Diagnostics, Switzerland). Its performance using open reagents from Denka Seiken (Japan), Roche, and Sekisui was also evaluated. RESULTS: The total coefficients of variation (CV) for all analytes were 1.0–2.7%. Linearity was observed for all analytes over the entire tested analytical range (R²≥0.99). The results of JCA-BM6010/C strongly correlated (r≥0.988) with those of Cobas 8000 for all evaluated analytes except LDH (r=0.963), as well as for all open reagents. Recovery rates for creatinine, glucose, calcium, and uric acid were 96.6–101.5% and 98.7–109.3% with the JEOL exclusive and open reagents, respectively. Sample carryover was less than 0.34%. CONCLUSIONS: JCA-BM6010/C showed acceptable performance in the precision, linearity, correlation, accuracy, and sample carryover analyses and in the method comparison. Therefore, it could be a useful routine laboratory medical analyzer.

Clinical Usefulness of Combined Cardiac Marker Testing with a Point-of-Care Device at the Emergency Department

BACKGROUND: B-type natriuretic peptide (BNP) levels are elevated in various conditions unrelated to heart failure, such as acute coronary syndrome, and cardiac troponin (cTn) levels may also be elevated in several non-ischemic conditions. This study aimed to evaluate the clinical usefulness of combined cardiac marker testing (BNP and cTnI) with point-of-care devices in patients who presented to the emergency department (ED). METHODS: Two thousand six hundred and seventy-four consecutive patients who visited the ED from March to August 2013 were included in this study. Cardiac marker testing was performed using the Triage Cardio3 panel (Alere, USA). Electronic medical records were collected on August 2014. RESULTS: We found that 22.2% patients had elevated BNP and/or cTnI (12.8% with only elevated BNP, 4.4% with only elevated cTnI, and 5.0% with both elevations). Patients with elevations in both marker levels showed significantly higher admission rate (78.5% vs. 62.7%, P=0.006) and longer length of hospital stay (11 vs. 6 days, P=0.001) than those with only elevated cTnI. Patients with elevations in both marker levels also showed higher admission rate (78.5% vs. 67.3%, P=0.016) and higher BNP levels (430 vs. 194 pg/mL, P<0.001) than those with only elevated BNP. CONCLUSIONS: Concurrent elevation of BNP and cTnI may be associated with inferior clinical outcome and combined testing of cTnI and BNP levels with high sensitivity would provide important information for assisting management decisions at the ED.

Establishing Reference Intervals for Soluble ST2 Assay in a Korean Population

BACKGROUND: Soluble ST2 (sST2) has emerged as a biomarker of heart failure. Previous studies indicated 35 ng/mL of sST2 as the clinically prognostic cut-off value. This study aims to establish reference intervals in a Korean population using an sST2 assay and to evaluate the applicability of the cut-off value. METHODS: From March to May 2014, sST2 levels were assayed in serum samples of 255 cardio-healthy Koreans (128 men and 127 women) using the Presage ST2 ELISA kit (Critical Diagnostics, USA). The reference interval for sST2 was defined using the nonparametric percentile method according to the CLSI EP28-A3c guideline. RESULTS: The median sST2 concentrations were 23.8 ng/mL (interquartile range (IQR), 19.0-28.7), 26.6 ng/mL (IQR, 21.0-30.9), and 21.9 ng/mL (IQR, 17.3-26.5) for the entire cohort, men, and women, respectively. sST2 levels were significantly higher in men than in women (P<0.0001). The 97.5th percentile upper reference limits for sST2 were 43.8 ng/mL, 49.6 ng/mL, and 35.4 ng/mL for the cohort, men, and women, respectively. Gender-specific upper reference limits were similar to limits reported by other studies. CONCLUSIONS: We suggest that gender-specific reference intervals should be used for the Korean population, as application of a single cut-off value of 35 ng/mL may be overcautious of the possibility of false positivity, especially in men.

Clinical Utility of Measurement of Vitamin D-Binding Protein and Calculation of Bioavailable Vitamin D in Assessment of Vitamin D Status

BACKGROUND: The associations of vitamin D deficiency with various clinical conditions highlighted the importance of vitamin D testing. Currently, clinicians measure only the total 25-hydroxyvitamin D [25(OH)D] concentration, regardless of its bioavailability. We aimed to determine the effect of vitamin D-binding protein (VDBP) on 25(OH)D bioavailability. METHODS: Serum samples were collected from 60 healthy controls, 50 pregnant women, and 50 patients in intensive care units (ICUs). Total 25(OH)D was quantified by liquid chromatography with tandem mass spectrometry, and VDBP levels were determined by using an ELISA kit (R&D Systems, USA). The bioavailable 25(OH)D levels were calculated by using total 25(OH)D, VDBP, and albumin concentrations. RESULTS: In comparison with healthy controls, the total 25(OH)D concentration was significantly lower in ICU patients (median, 11.65 vs 18.25 ng/mL; P<0.00001), but no significant difference was noted between pregnant women (18.25 ng/mL) and healthy controls. The VDBP level was significantly lower in ICU patients (95.58 vs 167.18 µg/mL, P=0.0002) and higher in pregnant women (225.01 vs 167.18 µg/mL, P=0.008) compared with healthy controls. Nonetheless, the calculated bioavailable 25(OH)D levels of ICU patients and pregnant women were significantly lower than those of healthy controls (1.97 and 1.93 ng/mL vs 2.56 ng/mL; P=0.0073 and 0.0027). CONCLUSIONS: A single marker of the total 25(OH)D level is not sufficient to accurately evaluate vitamin D status, especially in pregnant women. In cases where VDBP concentrations may be altered, VDBP measurements and bioavailable 25(OH)D calculations may help to determine vitamin D status accurately.

Analytical Evaluation of the DiaSys Albumin in Urine/CSF FS Kit for Urine Albumin Measurement Using a JEOL BioMajesty JCA-BM6010/C Analyzer

BACKGROUND: High albuminuria is defined as albumin excretion of >30 mg/24 hr or an albumin-to-creatinine ratio of 30 mg/g in a random urine sample. We assessed the analytical performance of the Albumin in Urine/CSF FS kit (DiaSys Inc., UK) using a BioMajesty JCA-6010/C analyzer (JEOL Inc., Japan). METHODS: Urine albumin concentrations were measured by the Albumin in Urine/CSF FS kit using a BioMajesty JCA-BM6010/C analyzer. Imprecision, linearity, and carry-over were measured according to the Clinical Laboratory and Standards Institute documents EP10 and EP9. The assay was compared with the ALB-T TQ Gen.2 (Roche, Germany) assay on a Cobas8000 C702 (Roche, Germany), the Tina-Quant Albumin (Roche, Switzerland) assay on a Hitachi7600-210 (Hitachi, Japan), and an Abbott urine albumin assay (Abbott Laboratories, USA) on a TBA 200FR (Toshiba, Japan) using 50 random urine samples. RESULTS: Within-run and total imprecision were 0.551-1.023% and 0.551-1.214%, respectively. Linearity ranged from 6.31 to 30.60 mg/dL, and functional sensitivity was 0.5 mg/dL. Results from the Albumin in Urine/CSF FS kit showed good correlation with the ALB-T TQ Gen.2 (r=0.987) and the Tina-Quant Albumin assays (r=0.991). However, the four assays categorized 18 of 50 urine samples into different albuminuria groups. CONCLUSIONS: Albumin in Urine/CSF FS testing on a BioMajesty JCA-BM6010/C analyzer showed good linearity, functional sensitivity, precision, and correlation with the ALB-T TQ Gen.2 and Tina-Quant Albumin assays. However, because some samples were categorized into different albuminuria groups by the different assays, further studies on the standardization of albuminuria assays are needed.