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.

Proenkephalin Predicts Organ Failure, Renal Replacement Therapy, and Mortality in Patients With Sepsis

Background@#Kidney failure occurs frequently and is associated with high mortality during sepsis. Proenkephalin (PENK) is an emerging biomarker of kidney function. We explored whether PENK levels could predict severity, organ failure, and mortality in septic patients. @*Methods@#We measured the PENK level in the plasma of 215 septic patients using the sphingotest penKid assay (Sphingotec GmbH, Hennigsdorf, Germany). This was analyzed in terms of sepsis severity, vasopressor use, 30-day mortality, sequential organ failure assessment (SOFA) renal subscore, the Chronic Kidney Disease Epidemiology Collaboration estimated glomerular filtration rate (CKD-EPI eGFR) categories, and renal replacement therapy (RRT) requirement. @*Results@#The PENK levels were significantly higher in patients with septic shock, vasopressor use, and non-survivors than in patients with solitary sepsis, no vasopressor use, and survivors, respectively (P = 0.02, P = 0.007, P < 0.001, respectively). The PENK levels were significantly associated with SOFA renal subscore and CKD-EPI eGFR categories (both P < 0.001). The distribution of lower eGFR ( < 60 mL/min/1.73 m2 ), RRT requirement, SOFA renal subscore, and the number of organ failures differed significantly according to the PENK quartile (P for trend < 0.001 or 0.017). The 30-day mortality rate also differed significantly according to the PENK quartile (P for trend < 0.001). @*Conclusions@#PENK could be an objective and reliable marker to predict severity, organ failure, and 30-day mortality in septic patients.

HDL Subclass Analysis in Predicting Metabolic Syndrome in Koreans With High HDL Cholesterol Levels

BACKGROUND: High-density lipoprotein cholesterol (HDL-C) is a complex mixture of subclasses with heterogeneous atheroprotective activities. We analyzed HDL-C subclass in relation to cardiovascular risk and metabolic syndrome (MetS) in a population with high HDL-C levels.METHODS: A total of 300 Korean individuals with high HDL-C levels (≥2.331 mmol/L) were enrolled following a comprehensive general medical examination including body composition analysis. HDL3-C levels were measured using the HDL3-EX SEIKEN kit (Randox Ltd., Crumlin, UK) and non-HDL3-C levels were calculated by subtracting HDL3-C levels from total HDL-C levels.RESULTS: HDL3-C levels and HDL3-C proportion had a weak positive correlation with low-density lipoprotein cholesterol (LDL-C) and triglycerides (r=0.21, r=0.25; r=0.26, r=0.34, respectively, all P<0.001); in contrast, non-HDL3-C levels had a weak negative correlation with these parameters (r=−0.17 and r=−0.25, respectively, both P<0.005). HDL3-C levels and HDL3-C proportion were significantly higher in the MetS group (N=8) than in the non-MetS group (0.71 vs 0.63 mmol/L, P=0.001; 29.7 vs 25.8%, P=0.001, respectively); these were the only predictors of MetS among the lipid variables (areas under the curves [AUC]=0.84 and 0.83, respectively, both P=0.001).CONCLUSIONS: In populations with high HDL-C levels, HDL-C subclass may provide a greater amount of information on cardiovascular risk and MetS than HDL-C levels alone.

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.

Hepcidin and Neutrophil Gelatinase-Associated Lipocalin as a Biomarker for Acute Kidney Injury Linked Iron Metabolism

No abstract available.

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.

Advances in Automated Urinalysis Systems, Flow Cytometry and Digitized Microscopy

No abstract available.

Neutrophil Gelatinase-Associated Lipocalin as a Promising Novel Biomarker for Early Detection of Kidney Injury

No abstract available.

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.

Prognostic Role of High-sensitivity Cardiac Troponin I and Soluble Suppression of Tumorigenicity-2 in Surgical Intensive Care Unit Patients Undergoing Non-cardiac Surgery

BACKGROUND: The prognostic utility of cardiac biomarkers, high-sensitivity cardiac troponin I (hs-cTnI) and soluble suppression of tumorigenicity-2 (sST2), in non-cardiac surgery is not well-defined. We evaluated hs-cTnI and sST2 as predictors of 30-day major adverse cardiac events (MACE) in patients admitted to the surgical intensive care unit (SICU) following major non-cardiac surgery. METHODS: hs-cTnI and sST2 concentrations were measured in 175 SICU patients immediately following surgery and for three days postoperatively. The results were analyzed in relation to 30-day MACE and were compared with the revised Goldman cardiac risk index (RCRI) score. RESULTS: Overall, 30-day MACE was observed in 16 (9.1%) patients. hs-cTnI and sST2 concentrations differed significantly between the two groups with and without 30-day MACE (P < 0.05). The maximum concentration of sST2 was an independent predictor of 30-day MACE (odds ratio=1.016, P=0.008). The optimal cut-off values of hs-cTnI and sST2 for predicting 30-day MACE were 53.0 ng/L and 182.5 ng/mL, respectively. A combination of hs-cTnI and sST2 predicted 30-day MACE better than the RCRI score. Moreover, 30-day MACE was observed more frequently with increasing numbers of above-optimal cut-off hs-cTnI and sST2 values (P < 0.0001). Reclassification analyses indicated that the addition of biomarkers to RCRI scores improved the prediction of 30-day MACE. CONCLUSIONS: This study demonstrates the utility of hs-cTnI and sST2 in predicting 30-day MACE following non-cardiac surgery. Cardiac biomarkers would provide enhanced risk stratification in addition to clinical RCRI scores for patients undergoing major non-cardiac surgery.

Mac-2 Binding Protein Glycosylation Isomer: Emerging Non-Invasive Serum Marker for Liver Fibrosis

No abstract available.

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.

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.

Quality Management of Hematology Tests in Blood Center / 대한수혈학회지

The primary goal in transfusion medicine is to promote high standards of quality in all aspects of transfusion, including production, management, and transfusion of blood components. To achieve this goal, a transfusion service quality management system should be established. Such a system should include several organizational structures, responsibilities, policies, processes, procedures, and resources with provided specifications and regulations. In this review, we summarize the current knowledge and practices regarding the quality management of hematology tests applied to the donor selection and production of blood components, including red blood cells, platelets, fresh frozen plasma, and cryoprecipitates in the field at blood centers.

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.

Comparison Between Soluble ST2 and High-Sensitivity Troponin I in Predicting Short-Term Mortality for Patients Presenting to the Emergency Department With Chest Pain

BACKGROUND: High-sensitivity cardiac troponin I (hs-cTnI) and the soluble isoform of suppression of tumorigenicity 2 (sST2) are useful prognostic biomarkers in acute coronary syndrome (ACS). The aim of this study was to test the short term prognostic value of sST2 compared with hs-cTnI in patients with chest pain. METHODS: Assays for hs-cTnI and sST2 were performed in 157 patients admitted to the Emergency Department (ED) for chest pain at arrival. In-hospital and 30-day follow-up mortalities were assessed. RESULTS: The incidence of ACS was 37%; 33 patients were diagnosed with ST elevation myocardial infarction (STEMI), and 25 were diagnosed with non-ST elevation myocardial infarction (NSTEMI). Compared with the no acute coronary syndrome (NO ACS) group, the median level of hs-cTnI was higher in ACS patients: 7.22 (5.24-14) pg/mL vs 68 (15.33-163.50) pg/mL (P35 ng/mL at ED arrival died during the 30-day follow-up. CONCLUSIONS: sST2 has a greater prognostic value for 30-day cardiac mortality after discharge in patients presenting to the ED for chest pain compared with hs-cTnI. In STEMI patients, an sST2 value >35 ng/mL at ED arrival showed the highest predictive power for short-term mortality.

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.