Original Article2021-05-01

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

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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.

Brief Communication2021-05-01

A Novel Species of the Genus Arsenicicoccus Isolated From Human Blood Using Whole-Genome Sequencing

Ji Hun Jeong , M.D., Ph.D., Oh Joo Kweon , M.D., Hye Ryoun Kim , M.D., Ph.D., Tae-Hyoung Kim , M.D., Ph.D., Sung-min Ha , Ph.D., and Mi-Kyung Lee , M.D., Ph.D.

Ann Lab Med 2021; 41(3): 323-327

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Abstract : Whole-genome sequencing (WGS) is an easily accessible and valuable tool in clinical microbiology, which can be used for identifying novel and rare species. We isolated gram-positive cocci from the blood of a pediatric patient, which could not be phenotypically identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) (BioMérieux, Marcy-l’Étoile, France). We could not identify the isolate to the species level using 16S ribosomal RNA (rRNA) sequencing. WGS was performed using the Illumina MiSeq platform (Illumina, San Diego, CA, USA); however, the subsequent genomic sequence database search using the TrueBac ID-Genome system (ChunLab, Inc., Seoul, Korea) did not yield any hits with an average nucleotide identity value >95.0%, which is the cut-off for species-level identification. Phylogenetic analysis suggested that the isolate belonged to a new Arsenicicoccus species, forming a subcluster with Arsenicicoccus bolidensis. Our data demonstrate that WGS allows a more accurate annotation of microbial genomes than other clinical microbiology tools, such as MALDI-TOF MS and 16S rRNA sequencing. This is the first report of the isolation of a novel Arsenicicoccus species from a clinical sample.

Original Article2022-01-01
Diagnostic Immunology

Comparison of the Automated Fluorescent Immunoassay System With Roche Elecsys and Beckman Coulter Access 2 Assays for Anti-Müllerian Hormone Measurement

Aera Han , M.D., Ph.D., Borum Suh , M.D., Gwang Yi , M.D., Yoo Jin Lee , M.D., and Sung Eun Kim , M.D.

Ann Lab Med 2022; 42(1): 47-53

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Abstract : Background: Since 2017, automated assays have been used in most clinical laboratories for anti-Müllerian hormone (AMH) level measurement. We evaluated the analytical performance of the newly developed automated fluorescent immunoassay system (AFIAS) AMH assay (Boditech Med, Gangwon-do, Korea) in comparison with the Roche Elecsys and Beckman Coulter Access 2 AMH assays. Methods: Analytical performance of the AFIAS AMH assay was assessed in terms of linearity, repeatability, and within-laboratory precision (CV%) using human recombinant AMH samples according to the Clinical and Laboratory Standards Institute (CLSI) guidelines EP05 and EP06. Using 293 serum samples collected from an infertility clinic, the AMH levels were compared across AFIAS, Elecsys, and Access 2 AMH assays according to the CLSI EP09 guidelines. Results: The AFIAS AMH assay results were linear across the measurement range of 0.420–72.386 pmol/L AMH, with repeatability of 6.341%. CV% of the AFIAS AMH assay for three levels of control, 1.786, 7.143, and 56.857 pmol/L, were 5.801%, 5.714%, and 6.228%, respectively. The results of the three AMH assays showed strong correlation: AFIAS and Elecsys [slope, 1.055 (95% confidence interval (CI), 1.022–1.088) and Spearman’s rho, 0.978 (95% CI, 0.973–0.983)], Elecsys and Access 2 [slope, 0.813 (95% CI, 0.791–0.834) and Spearman’s rho, 0.986 (95% CI, 0.983–0.989)], and AFIAS and Access 2 [slope, 0.836 (95% CI, 0.821–0.853) and Spearman’s rho, 0.984 (95% CI, 0.980–0.988)]. Conclusions: The AFIAS AMH assay may be an alternative to the Roche Elecsys and Beckman Coulter Access 2 AMH assays.

Original Article2021-09-01
Clinical Microbiology

Risk Factors for Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Community-Onset Bloodstream Infection: Impact on Long-Term Care Hospitals in Korea

Yae Jee Baek , M.D., Young Ah Kim , M.D., Dokyun Kim , M.D., Jong Hee Shin , M.D., Young Uh , M.D., Kyeong Seob Shin , M.D., Jeong Hwan Shin , M.D., Seok Hoon Jeong , M.D., Geun Woo Lee , M.P.H., Eun Ji Lee , M.S, Dong-Sook Kim , Ph.D., Yoon Soo Park , M.D., Ph.D.

Ann Lab Med 2021; 41(5): 455-462

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Abstract : Background: The prevalence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) in the community has increased worldwide due to multifactorial reasons. ESBL-EC bloodstream infection (BSI) complicates the decision for proper antimicrobial administration. In this multicenter study, we investigated the prevalence, risk factors, and molecular background of community-onset (CO) ESBL-EC BSI. Methods: We included data for all episodes of ESBL-EC BSI of community origin from May 2016 to April 2017 obtained from the Korean national antimicrobial resistance surveillance system, which comprises six sentinel hospitals. Data, including previous history of admission and use of antimicrobials and medical devices before BSI, were collected, along with microbiological analysis results. Results: Among 1,189 patients with CO BSI caused by E. coli, 316 (27%) were identified as ESBL producers. History of admission, especially to a long-term care hospital (LTCH), and previous use of β-lactams/β-lactamase inhibitors, carbapenem, lincosamide, aminoglycoside, and extended-spectrum cephalosporin were independent risk factors for CO ESBL-EC BSI; admission to an LTCH showed the highest odds ratio (3.8, 95% confidence interval 2.3-6.1). The most common genotype was CTX-M-15 (N=131, 41%), followed by CTX-M-14 (N=86, 27%). ST131 was the most common sequence type among ESBL-EC groups (57%). Conclusions: In Korea, 27% of CO E. coli BSI were caused by ESBL producers. From perspectives of empirical treatment and infection control, history of admission to an LTCH and antimicrobial use should be noted.

Original Article2021-07-01
Diagnostic Genetics

Clinical Application of Sequential Epigenetic Analysis for Diagnosis of Silver–Russell Syndrome

Soo Yeon Kim , M.D., Chang Ho Shin , M.D., Young Ah Lee , M.D., Ph.D., Choong Ho Shin , M.D., Ph.D., Sei Won Yang , M.D., Ph.D., Tae-Joon Cho , M.D., Ph.D., and Jung Min Ko , M.D., Ph.D.

Ann Lab Med 2021; 41(4): 401-408

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Abstract : Background: Silver-Russell syndrome (SRS) is a pre- or post-natal growth retardation disorder caused by (epi)genetic alterations. We evaluated the molecular basis and clinical value of sequential epigenetic analysis in pediatric patients with SRS. Methods: Twenty-eight patients who met≥3 Netchine-Harbison clinical scoring system (NH-CSS) criteria for SRS were enrolled;26 (92.9%) were born small for gestational age, and 25 (89.3%) showed postnatal growth failure. Relative macrocephaly, body asymmetry, and feeding difficulty were noted in 18 (64.3%), 13 (46.4%), and 9 (32.1%) patients, respectively. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) on chromosome 11p15 was performed as the first diagnostic step. Subsequently, bisulfite pyrosequencing (BP) for imprinting center 1 and 2 (IC1 and IC2) at chromosome 11p15, MEST on chromosome 7q32.2, and MEG3 on chromosome 14q32.2 was performed. Results:. Seventeen (60.7%) patients exhibited methylation defects, including loss of IC1 methylation (N=14; 11 detected by MS-MLPA and three detected by BP) and maternal uniparental disomy 7 (N=3). The diagnostic yield was comparable between patients who met three or four of the NH-CSS criteria (53.8% vs 50.0%). Patients with methylation defects responded better to growth hormone treatment. Conclusions: NH-CSS is a powerful tool for SRS screening. However, in practice, genetic analysis should be considered even in patients with a low NH-CSS score. BP analysis detected additional methylation defects that were missed by MS-MLPA and might be considered as a first-line diagnostic tool for SRS.

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

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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.

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

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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 Article2022-01-01
Clinical Microbiology

Genotypic Distribution and Antimicrobial Susceptibilities of Carbapenemase-Producing Enterobacteriaceae Isolated From Rectal and Clinical Samples in Korean University Hospitals Between 2016 and 2019

Seri Jeong , M.D., Nuri Lee , M.D., Min-Jeong Park , M.D., Kibum Jeon , M.D., Han-Sung Kim , M.D., Hyun Soo Kim , M.D., Jae-Seok Kim , M.D., and Wonkeun Song , M.D., Ph.D.

Ann Lab Med 2022; 42(1): 36-46

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Abstract : Background: The emergence of carbapenemase-producing Enterobacteriaceae (CPE) represents a major clinical problem. Recently, the occurrence of CPE has increased globally, but epidemiological patterns vary across region. We report the trends in the genotypic distribution and antimicrobial susceptibility of CPE isolated from rectal and clinical samples during a four-year period. Methods: Between January 2016 and December 2019, 1,254 nonduplicated CPE isolates were obtained from four university hospitals in Korea. Carbapenemase genotypes were determined by multiplex real-time PCR. Antimicrobial susceptibility was profiled using the Vitek 2 system (bioMérieux, Hazelwood, MO, USA) or MicroScan Walkaway-96 system (Siemens West Sacramento, CA, USA). The proportions of carbapenemase genotypes and nonsusceptibility were analyzed using Pearson’s chi-square test. Results: Among the 1,254 CPE isolates, 486 (38.8%), 371 (29.6%), 357 (28.5%), 8 (0.6%), 8 (0.6%), and 24 (1.9%) were Klebsiella pneumoniae carbapenemase (KPC), oxacillinase (OXA)-48-like, New Delhi metallo-β-lactamase (NDM), imipenemase (IMP), Verona integron-encoded metallo-β-lactamase (VIM), and multiple producers, respectively. The predominant species was K. pneumoniae (72.6%), followed by Escherichia coli (6.5%). More than 90% of the isolates harboring KPC, NDM, and OXA-48-like were nonsusceptible to cephalosporins, aztreonam, and carbapenems. Conclusions: The impact of CPE is primarily due to KPC-, NDM-, and OXA-48-like-producing K. pneumoniae isolates. Isolates carrying these carbapenemase are mostly multidrug-resistant. Control strategies based on these genotypic distributions and antimicrobial susceptibilities of CPE isolates are required.

Original Article2021-03-01
Diagnostic Immunology

Prediction of HLA-DQ in Deceased Donors and its Clinical Significance in Kidney Transplantation

Soo-Kyung Kim , M.D., Ph.D., John Jeongseok Yang , M.D., Sang-Hyun Hwang , M.D., Ph.D., Heungsup Sung , M.D., Ph.D., Sung Shin , M.D., Ph.D., Sun-Young Ko , M.D., Ph.D., and Heung-Bum Oh , M.D., Ph.D.

Ann Lab Med 2021; 41(2): 190-197

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Abstract : Background: HLA-DQ typing in deceased donors is not mandatory in Korea. Therefore, when patients develop DQ antibodies after kidney transplantation (KT) from deceased donor, it is impossible to determine whether they are donor-specific antibodies (DSA). We developed DQ prediction programs for the HLA gene and evaluated their clinical utility. Methods: Two HLA-DQ prediction programs were developed: one based on Lewontin’s linkage disequilibrium (LD) and haplotype frequency and the other on an artificial neural network (ANN). Low-resolution HLA-A, -B, -DR, and -DQ typing data of 5,603 Korean patients were analyzed in terms of haplotype frequency and used to develop an ANN DQ prediction program. Predicted DQ (pDQ) genotype accuracy was analyzed using the typed DQ data of 403 patients. pDQ DSA agreement, sensitivity, specificity, and false-negative rate was evaluated using 1,970 single-antigen bead assays performed on 885 KT recipients. The clinical significance of DQ and pDQ DSA was evaluated in 411 KT recipients. Results: pDQ genotype accuracies were 75.4% (LD algorithm) and 75.7% (ANN). When the second most likely pDQ (LD algorithm) was also considered, the genotype accuracy increased to 92.6%. pDQ DSA (LD algorithm) agreement, sensitivity, specificity, and false-negative rate were 97.5%, 97.3%, 98.6%, and 2.4%, respectively. The antibody-mediated rejection treatment frequency was significantly higher in DQ or pDQ DSA-positive patients than in DQ or pDQ DSA-negative patients (P<0.001). Conclusions: Our DQ prediction programs showed good accuracy and could aid DQ DSA detection in patients who had undergone deceased donor KT without donor HLA-DQ typing.

Letter to the Editor2022-01-01
Clinical Microbiology

Rates of Coinfection Between SARS-CoV-2 and Other Respiratory Viruses in Korea

Young-gon Kim , M.D., Hyunwoong Park , M.D., Ph.D., So Yeon Kim , M.D., Ph.D., Ki Ho Hong , M.D., Ph.D., Man Jin Kim , M.D., Jee-Soo Lee , M.D., Sung-Sup Park , M.D., Ph.D., and Moon-Woo Seong , M.D., Ph.D.

Ann Lab Med 2022; 42(1): 110-112

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