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  • Original Article2022-03-01 Clinical Microbiology

    Virulence Factors Associated With Escherichia coli Bacteremia and Urinary Tract Infection

    Bongyoung Kim , M.D., Ph.D., Jin-Hong Kim , M.D., and Yangsoon Lee , M.D., Ph.D.

    Ann Lab Med 2022; 42(2): 203-212

    Abstract : Background: Extraintestinal pathogenic Escherichia coli (ExPEC) causes various infections, including urinary tract infection (UTI), sepsis, and neonatal meningitis. ExPEC strains have virulence factors (VFs) that facilitate infection by allowing bacterial cells to migrate into and multiply within the host. We compared the microbiological characteristics of ExPEC isolates from blood and urine specimens from UTI patients. Methods: We conducted a single-center, prospective study in an 855-bed tertiary-care hospital in Korea. We consecutively recruited 80 hospitalized UTI patients with E. coli isolates, which were isolated from blood and/or urine, and urine alone between March 2019 and May 2020. We evaluated the 80 E. coli isolates for the presence of bacterial genes encoding the sequence types (STs), antimicrobial resistance, and VFs using whole-genome sequencing (WGS). Results: We found no significant differences in STs, antimicrobial resistance patterns, or VFs between isolates from blood and urine specimens. ST131, a pandemic multidrug-resistant clone present in both blood and urine, was the most frequent ST (N=19/80, 24%), and ST131 isolates carried more virulence genes, especially, tsh and espC, than non-ST131 isolates. The virulence scores of the ST131 group and the ST69, ST95, and ST1193 groups differed significantly (P

  • Original Article2021-09-01 Clinical Chemistry

    Internal Quality Control Data of Urine Reagent Strip Tests and Derivation of Control Rules Based on Sigma Metrics

    Haeil Park , M.D., Ph.D. and Younsuk Ko , M.T.

    Ann Lab Med 2021; 41(5): 447-454

    Abstract : Background: Urine reagent strip test (URST) results are semi-quantitative; therefore, the precision of URSTs is evaluated as the proportion of categorical results from repeated measurements of a sample that are concordant with an expected result. However, URSTs have quantitative readout values before ordinal results challenging statistical monitoring for internal quality control (IQC) with control rules. This study aimed to determine the sigma metric of URSTs and derive appropriate control rules for IQC. Methods: The URiSCAN Super Plus fully automated urine analyzer (YD Diagnostics, Yongin, Korea) was used for URSTs. Change in reflectance rate (change %R) data from IQC for URSTs performed between November 2018 and May 2020 were analyzed. Red blood cells, bilirubin, urobilinogen, ketones, protein, glucose, leukocytes, and pH were measured from 2-3 levels of control materials. The total allowable error (TEa) for a grade was the difference in midpoints of a predefined change %R range between two adjacent grades. The sigma metric was calculated as TEa/SD. Sigma metric-based control rules were determined with Westgard EZ Rules 3 software (Westgard QC, Madison, WI, USA). Results: Seven out of the eight analytes had a sigma metric >4 in the control materials with a negative grade (-), which were closer to the cut-offs. Corresponding control rules ranged from 12.5s to 13.5s. Conclusions: Although the URST is a semi-quantitative test, statistical IQC can be performed using the readout values. According to the sigma metric, control rules recommended for URST IQC in routine clinical practice are 12.5s to 13.5s.

  • Letter to the Editor2021-09-01 Clinical Microbiology

    Serological Evidence of Coxiella burnetii and SARS-CoV-2 Co-infection: A Case Report

    Hee Sue Park , M.D., Ph.D., Pan Kee Bae , Ph.D., Hye Won Jeong , M.D., Ph.D., Bo Ra Son , M.D., Ph.D., and Kyeong Seob Shin , M.D., Ph.D.

    Ann Lab Med 2021; 41(5): 510-513
  • Guideline2022-09-01 Clinical Microbiology

    Guidelines for Mobile Laboratories for Molecular Diagnostic Testing of COVID-19

    Kyoung Ho Roh , M.D., Ki Ho Hong , M.D., Myung-Hyun Nam , M.D., Taek Soo Kim , M.D., Moon-Woo Seong , M.D., Jin Kyung Lee , M.D., Sookyoung Bae , M.D., Hee Jae Huh , M.D., Jeong-Yeal Ahn , M.D., Jinsook Lim , M.D., Gab Jung Kim , Ph.D., Jae Sun Park , Ph.D., Hyun Yeong Kim , Ph.D., Cheon Kwon Yoo , Ph.D., and Hyukmin Lee , M.D. on behalf of Korean Society for Laboratory Medicine, COVID-19 Task Force, and the Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency

    Ann Lab Med 2022; 42(5): 507-514

    Abstract : With the rapid spread of the coronavirus disease (COVID-19), the need for rapid testing and diagnosis and consequently, the demand for mobile laboratories have increased. Despite this need, there are no clear guidelines for the operation, maintenance, or quality control of mobile laboratories. We provide guidelines for the operation, management, and quality control of mobile laboratories, and specifically for the implementation and execution of COVID-19 molecular diagnostic testing. These practical guidelines are primarily based on expert opinions and a laboratory accreditation inspection checklist. The scope of these guidelines includes the facility, preoperative evaluation, PCR testing, internal and external quality control, sample handling, reporting, laboratory personnel, biosafety level, and laboratory safety management. These guidelines are useful for the maintenance and operation of mobile laboratories not only in normal circumstances but also during public health crises and emergencies.

  • Original Article2021-05-01 Diagnostic Hematology

    Immune Checkpoint Programmed Cell Death Protein-1 (PD-1) Expression on Bone Marrow T Cell Subsets in Patients With Plasma Cell Myeloma

    Min Young Lee , M.D., Ph.D., Chan-Jeoung Park , M.D., Ph.D., Young-Uk Cho , M.D., Ph.D., Eunkyoung You , M.D., Ph.D., Seongsoo Jang , M.D., Ph.D., Eul Ju Seo , M.D., Ph.D., Jung-Hee Lee , M.D., Ph.D., Dok Hyun Yoon , M.D., Ph.D., and Cheolwon Suh , M.D., Ph.D.

    Ann Lab Med 2021; 41(3): 259-267

    Abstract : Background: Plasma cell myeloma (PCM) is caused by immune dysregulation. We evaluated the expression of immune checkpoint programmed cell death protein-1 (PD-1) on T cell subsets in PCM patients according to disease course and cytogenetic abnormalities. This study aimed to find a target group suitable for therapeutic use of PD-1 blockade in PCM. Methods: A total of 188 bone marrow (BM) samples from 166 PCM patients and 32 controls were prospectively collected between May 2016 and May 2017. PD-1 expression on BM T cell subsets was measured using flow cytometry. Results: At diagnosis, the median PD-1 expression on CD4+ T cells was 24.6%, which did not significantly differ from that in controls. After stem cell transplantation, PD-1 expression on CD4+ T cells was higher than that at diagnosis (P

  • Brief Communication2021-07-01 Clinical Chemistry

    Concordance of Three Automated Procalcitonin Immunoassays at Medical Decision Points

    Hae Weon Cho , M.D., Sun Hee Kim , M.T., Yonggeun Cho , M.D., Seok Hoon Jeong , M.D., Ph.D., and Sang-Guk Lee , M.D., Ph.D.

    Ann Lab Med 2021; 41(4): 419-423

    Abstract : Procalcitonin (PCT) is a useful bacterial infection biomarker with the potential for guiding antibiotic therapy. We evaluated the concordance of three automated PCT immunoassays: Kryptor (BRAHMS GmbH, Hennigsdorf, Germany), Atellica IM 1600 (Siemens Healthcare Diagnostics, Munich, Germany), and Cobas e801 (Roche Diagnostics, Mannheim, Germany). In 119 serum samples with a PCT concentration

  • Brief Communication2022-03-01 Clinical Microbiology

    Serotype Distribution and Antimicrobial Resistance of Salmonella Isolates in Korea between 2016 and 2017

    Si Hyun Kim , Ph.D., Gyung-Hye Sung , Ph.D., Eun Hee Park , Ph.D., In Yeong Hwang , Ph.D., Gyu Ri Kim , Ph.D., Sae Am Song , M.D., Hae Kyung Lee , M.D., Young Uh , M.D., Young Ah Kim , M.D., Seok Hoon Jeong , M.D., Jong Hee Shin , M.D., Kyeong Seob Shin , M.D., Jaehyeon Lee , M.D., Joseph Jeong , M.D., Young Ree Kim , M.D., Dongeun Yong , M.D., Miae Lee , M.D., Yu Kyung Kim , M.D., Nam Hee Ryoo , M.D., Seungok Lee , M.D., Jayoung Kim , M.D., Sunjoo Kim , M.D., Hyun Soo Kim , M.D., and Jeong Hwan Shin , M.D.

    Ann Lab Med 2022; 42(2): 268-273

    Abstract : Salmonella is one of the major causes of food-borne infections. We investigated the serotype distribution and antimicrobial resistance of Salmonella isolates collected in Korea between January 2016 and December 2017. In total, 669 Salmonella isolates were collected from clinical specimens at 19 university hospitals. Serotyping was performed according to the Kauffmann–White scheme, and antimicrobial susceptibility was tested using Sensititre EUVSEC plates or disk diffusion. Among the strains, C (39.8%) and B (36.6%) were the most prevalent serogroups. In total, 51 serotypes were identified, and common serotypes were S. enterica serovar I 4,[5],12:i:- (16.7%), S. Enteritidis (16.1%), S. Bareilly (14.6%), S. Typhimurium (9.9%), and S. Infantis (6.9%). The resistance rates to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole were 32.6%, 12.1%, and 8.4%, respectively. The resistance rates to cefotaxime and ciprofloxacin were 8.1% and 3.0%, respectively, while 5.4% were multidrug-resistant. S. enterica serovar I 4,[5],12:i:- and S. Enteritidis were highly prevalent, and there was an increase in rare serotypes. Multidrug resistance and ciprofloxacin resistance were highly prevalent. Periodic investigations of Salmonella serotypes and antimicrobial resistance are needed.

  • Original Article2022-01-01 Diagnostic Immunology

    Association of HLA-DRB1 and -DQB1 Alleles with Susceptibility to IgA Nephropathy in Korean Patients

    Ji Won In , M.D., Kiwook Jung , M.D., Sue Shin , M.D., Ph.D., Kyoung Un Park , M.D., Ph.D., Hajeong Lee , M.D., Ph.D., and Eun Young Song , M.D., Ph.D.

    Ann Lab Med 2022; 42(1): 54-62

    Abstract : Background: Associations between IgA nephropathy (IgAN) and HLA-DRB1 and -DQB1 alleles have been reported in several ethnic groups. We investigated the association of HLA-DRB1 and -DQB1 alleles with the predisposition for IgAN and disease progression to end-stage kidney disease (ESKD) in Korean patients. Methods: We analyzed HLA-DRB1 and -DQB1 genotypes in 399 IgAN patients between January 2000 and January 2019 using a LIFECODES sequence-specific oligonucleotide (SSO) typing kit (Immucor, Stamford, CT, USA) or a LABType SSO Typing Test (One Lambda, Canoga Park, CA, USA). Alleles with a significant difference in two-digit resolution were further analyzed using in-house sequence-based typing and sequence-specific primer PCR. As controls, 613 healthy hematopoietic stem cell donors were included. Kidney survival was analyzed in 281 IgAN patients with available clinical and laboratory data using Cox regression analysis. Where needed, P-values were adjusted using Bonferroni correction. Results: The allele frequencies of HLA-DRB1*04:05 (corrected P [Pc]

  • Original Article2022-07-01 Clinical Chemistry

    Prognostic Utility of Procalcitonin, Presepsin, and the VACO Index for Predicting 30-day Mortality in Hospitalized COVID-19 Patients

    Mikyoung Park , M.D., Ph.D, Mina Hur , M.D., Ph.D, Hanah Kim , M.D., Ph.D, Chae Hoon Lee , M.D., Ph.D, Jong Ho Lee , M.D., Hyung Woo Kim , M.D., and Minjeong Nam , M.D., Ph.D.

    Ann Lab Med 2022; 42(4): 406-414

    Abstract : Background: Biomarkers and clinical indices have been investigated for predicting mortality in patients with coronavirus disease (COVID-19). We explored the prognostic utility of procalcitonin (PCT), presepsin, and the Veterans Health Administration COVID-19 (VACO) index for predicting 30-day-mortality in COVID-19 patients. Methods: In total, 54 hospitalized COVID-19 patients were enrolled. PCT and presepsin levels were measured using the Elecsys BRAHMS PCT assay (Roche Diagnostics GmbH, Mannheim, Germany) and HISCL Presepsin assay (Sysmex, Kobe, Japan), respectively. The VACO index was calculated based on age, sex, and comorbidities. PCT and presepsin levels and the VACO index were compared using ROC curve, Kaplan–Meier method, and reclassification analysis for the 30-day mortality. Results: ROC curve analysis was used to measure PCT and presepsin levels and the VACO index to predict 30-day mortality; the optimal cut-off values were 0.138 ng/mL for PCT, 717 pg/mL for presepsin, and 12.1% for the VACO index. On Kaplan–Meier survival analysis, hazard ratios (95% confidence interval) were 15.9 (4.1-61.3) for PCT, 26.3 (6.4-108.0) for presepsin, and 6.0 (1.7-21.1) for the VACO index. On reclassification analysis, PCT and presepsin in addition to the VACO index significantly improved the prognostic value of the index. Conclusions: This study demonstrated the prognostic utility of measuring PCT and presepsin levels and the VACO index in COVID-19 patients. The biomarkers in addition to the clinical index were more useful than the index alone for predicting clinical outcomes in COVID-19 patients.

  • Original Article2021-05-01 Clinical Chemistry

    Evaluation of the Barricor Tube in 28 Routine Chemical Tests and Its Impact on Turnaround Time in an Outpatient Clinic

    Soo Young Moon , M.D., Han Sol Lee , M.T., Min Soon Park , M.T., In-Suk Kim , M.D., Ph.D., and Sun Min Lee , M.D.

    Ann Lab Med 2021; 41(3): 277-284

    Abstract : Background: We recently introduced the Barricor (BD, Franklin Lakes, NJ, USA) plasma separation tube, which uses a mechanical separator instead of a gel. We evaluated the effects of using the Barricor tube in a stat (statin) laboratory on the results and turnaround time (TAT) of routine chemical tests. We verified the impact of Barricor tube on reducing TAT and providing results similar to those obtained using serum separator tubes (SSTs). Methods: We collected venous blood samples from 166 outpatients in Barricor tubes and SSTs and measured 28 routine analytes using an AU5800 instrument (Beckman Coulter, Brea, CA, USA). TAT indexes were compared before and after using Barricor tube. Results: Mean percent differences were 60 minutes decreased from 7.84% to 2.66%, which was approximately one-third of that for SST. The reduction in TAT was attributable to a decrease in centrifugation time. Incomplete clotting and repeated centrifugation, which occurred frequently when using SST, also decreased after using the Barricor tubes. Conclusions: The Barricor tube is an alternative to SST for routine chemical tests in institutions aiming to reduce TAT, with clinically allowable differences in test results.

Annals of Laboratory Medicine
Journal Information July, 2023
Vol.43 No.4
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