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  • Original Article2021-03-01

    Establishment of Pediatric Reference Intervals for Routine Laboratory Tests in Korean Population: A Retrospective Multicenter Analysis

    Ji Yeon Sung , M.D., Jong Do Seo , M.D., Dae-Hyun Ko , M.D., Min-Jeong Park , M.D., Sang Mee Hwang , M.D., Sohee Oh , Ph.D., Sail Chun , M.D., Moon-Woo Seong , M.D., Junghan Song , M.D., Sang Hoon Song , M.D., and Sung Sup Park , M.D.

    Ann Lab Med 2021; 41(2): 155-170

    Abstract : Background: Reference intervals defined for adults or children of other ethnicities cannot be applied in the evaluation of Korean pediatric patients. Pediatric reference intervals are difficult to establish because children are in their growing stage and their physiology changes continuously. We aimed to establish reference intervals for routine laboratory tests for Korean pediatric patients through retrospective multicenter data analysis. Methods: Preoperative laboratory test results from 1,031 pediatric patients aged 0 month–18 years who underwent minor surgeries in four university hospitals were collected. Age- and sex-specific reference intervals for routine laboratory tests were defined based on the Clinical and Laboratory Standards Institute (CLSI) EP28-A3c guidelines. Results: The pediatric reference intervals determined in this study were different from existing adult reference intervals and pediatric reference intervals for other ethnicities. Most tests required age-specific partitioning, and some of those required sex-specific partitioning for at least one age-partitioned subgroup. Erythrocyte sedimentation rate, monocyte percentage, basophil percentage, activated partial thromboplastin time, glucose, cholesterol, albumin, bilirubin, chloride, and C-reactive protein did not show any difference between age- or sex-partitioned subgroups. Conclusions: We determined Korean pediatric reference intervals for hematology, coagulation, and chemistry tests by indirect sampling based on medical record data from multiple institutions. These reference intervals would be valuable for clinical evaluations in the Korean pediatric population.

  • Review Article2022-05-01
    Diagnostic Genetics

    Current Issues, Challenges, and Future Perspectives of Genetic Counseling in Korea

    Namhee Kim , M.D., Sun-Young Kong , M.D., Ph.D., Jongha Yoo , M.D., Ph.D., Do-Hoon Kim , M.D., Ph.D., Soo Hyun Seo , M.D., and Jieun Kim , M.D., Ph.D.

    Ann Lab Med 2022; 42(3): 314-320

    Abstract : Genetic testing has become increasingly integrated into all areas of healthcare, and complex genetic testing usage continues to grow; thus, the demand for genetic counseling (GC) is likely to increase. However, it is unclear whether the current clinical GC capacity is sufficient for meeting the existing demand. This review describes the current issues, challenges, and future perspectives of GC in Korea based on a professional survey conducted among laboratory physicians. In view of the growing GC demand in the clinical setting, participants expressed a concern about the lack of support from the national healthcare insurance policy and legal requirements, such as certification, for GC practice. The implementation of genetic testing in the overall healthcare system in Korea is in an early phase. Proper implementation can be achieved through education and training of specialists, collaboration among healthcare personnel, proper regulatory oversight, genomic policies, and public awareness. Understanding the current GC capacity, issues, and challenges is a prerequisite for effective strategic planning by healthcare systems considering the expected growth in the demand for clinical genetic services over the next few decades.

  • Original Article2022-03-01

    Comparison of Non-Invasive Clinical Algorithms for Liver Fibrosis in Patients With Chronic Hepatitis B to Reduce the Need for Liver Biopsy: Application of Enhanced Liver Fibrosis and Mac-2 Binding Protein Glycosylation Isomer

    Mina Hur , M.D., Ph.D., Mikyoung Park , M.D., Ph.D., Hee-Won Moon , M.D., Ph.D., Won Hyeok Choe , M.D., Ph.D., and Chae Hoon Lee , M.D., Ph.D.

    Ann Lab Med 2022; 42(2): 249-257

    Abstract : Background: Non-invasive clinical algorithms for the detection of liver fibrosis (LF) can reduce the need for liver biopsy (LB). We explored the implementation of two serum biomarkers, enhanced liver fibrosis (ELF) and Mac-2 binding protein glycosylation isomer (M2BPGi), in clinical algorithms for LF in chronic hepatitis B (CHB) patients. Methods: Two clinical algorithms were applied to 152 CHB patients: (1) transient elastography (TE) followed by biomarkers (TE/ELF and TE/M2GPGi); (2) biomarker test followed by TE (ELF/TE and M2BPGi/TE). Using the cut-off value or index for the detection of advanced LF (TE≥F3; 9.8 in ELF and 3.0 in M2BPGi), LB was expected to be performed in cases with discordant TE and biomarker results. Results: In both algorithms, the expected number of LBs was lower when using M2BPGi than when using ELF (TE/ELF or ELF/TE, 13.2% [N=20]; TE/M2BPGi or M2BPGi/TE, 9.9% [N=15]), although there was no statistical difference (P=0.398). In the TE low-risk group (TE≤F2), the discordance rate was significantly lower in the TE/M2BPGi approach than in the TE/ELF approach (1.5% [2/136] vs. 11.0% [15/136], P=0.002). In the biomarker low-risk group, there was no significant difference between the ELF/TE and M2BPGi/TE approaches (3.9% [5/126] vs. 8.8% [13/147], P=0.118). Conclusions: Both ELF and M2BPGi can be implemented in non-invasive clinical algorithms for assessing LF in CHB patients. Given the lowest possibility of losing advanced LF cases in the low-risk group when using the TE/M2BPGi approach, this combination seems useful in clinical practice.

  • Review Article2022-09-01
    Clinical Chemistry

    Review of the Use of Liquid Chromatography-Tandem Mass Spectrometry in Clinical Laboratories: Part II–Operations

    Brian A. Rappold , B.S.

    Ann Lab Med 2022; 42(5): 531-557

    Abstract : Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is increasingly utilized in clinical laboratories because it has advantages in terms of specificity and sensitivity over other analytical technologies. These advantages come with additional responsibilities and challenges given that many assays and platforms are not provided to laboratories as a single kit or device. The skills, staff, and assays used in LC-MS/MS are internally developed by the laboratory, with relatively few exceptions. Hence, a laboratory that deploys LC-MS/MS assays must be conscientious of the practices and procedures adopted to overcome the challenges associated with the technology. This review discusses the post-development landscape of LC-MS/MS assays, including validation, quality assurance, operations, and troubleshooting. The content knowledge of LC-MS/MS users is quite broad and deep and spans multiple scientific fields, including biology, clinical chemistry, chromatography, engineering, and MS. However, there are no formal academic programs or specific literature to train laboratory staff on the fundamentals of LC-MS/MS beyond the reports on method development. Therefore, depending on their experience level, some readers may be familiar with aspects of the laboratory practices described herein, while others may be not. This review endeavors to assemble aspects of LC-MS/MS operations in the clinical laboratory to provide a framework for the thoughtful development and execution of LC-MS/MS applications.

  • 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

  • Brief Communication2021-07-01

    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

  • Original Article2021-05-01

    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

  • Original Article2021-03-01

    Quantification of Thioguanine in DNA Using Liquid Chromatography-Tandem Mass Spectrometry for Routine Thiopurine Drug Monitoring in Patients With Pediatric Acute Lymphoblastic Leukemia

    Rihwa Choi , M.D., Mi Ryung Chun , M.S., Jisook Park , Ph.D., Ji Won Lee , M.D., Ph.D., Hee Young Ju , M.D., Hee Won Cho , M.D., Ju Kyung Hyun , M.D., Hong Hoe Koo , M.D., Ph.D., Eun Sang Yi , M.D., and Soo-Youn Lee , M.D., Ph.D.

    Ann Lab Med 2021; 41(2): 145-154

    Abstract : Background: We developed an assay to measure DNA-incorporated 6-thioguanine (DNA-TG) and validated its clinical applicability in Korean pediatric patients with acute lymphoblastic leukemia (ALL) in order to improve individualized thiopurine treatment and reduce the life-threatening cytotoxicity. Methods: The DNA-TG assay was developed based on liquid chromatography-tandem mass spectrometry, with isotope-labeled TG-d3 and guanine-d3 as internal standards. This method was applied to 257 samples of pediatric ALL patients. The DNA-TG level was compared with erythrocyte TG nucleotide (RBC-TGN) level in relation to the TPMT and NUDT15 genotypes, which affect thiopurine metabolism, using Spearman’s rank test and repeated measure ANOVA. Results: For DNA-TG quantification, a linearity range of 10.0-5,000.0 fmol TG/μg DNA; bias for accuracy of –10.4% –3.5%; coefficient of variation for intra- and inter-day precision of 3.4% and 5.8% at 80 fmol TG/μg DNA and of 4.9% and 5.3% at 800 fmol TG/μg DNA, respectively; and recovery of 85.7%–116.2% were achieved without matrix effects or carry-over. The median DNA-TG level in the 257 samples was 106.0 fmol TG/μg DNA (interquartile range, 75.8–150.9). There was a strong correlation between DNA-TG and RBC-TGN levels (ρ=0.68, P<0.0001). The DNA-TG/RBC-TGN ratio was significantly higher in NUDT15 intermediate metabolizers (*1/*2 and *1/*3) than in patients with wild-type alleles (P<0.0001). Conclusions: This simple and sensitive method for measuring DNA-TG level can improve therapeutic drug monitoring for thiopurine treatment.

  • Review Article2022-09-01
    Diagnostic Hematology

    Unreliable Automated Complete Blood Count Results: Causes, Recognition, and Resolution

    Gene Gulati, Ph.D., Guldeep Uppal, M.D., and Jerald Gong, M.D.

    Ann Lab Med 2022; 42(5): 515-530

    Abstract : Automated hematology analyzers generate accurate complete blood counts (CBC) results on nearly all specimens. However, every laboratory encounters, at times, some specimens that yield no or inaccurate result(s) for one or more CBC parameters even when the analyzer is functioning properly and the manufacturer’s instructions are followed to the letter. Inaccurate results, which may adversely affect patient care, are clinically unreliable and require the attention of laboratory professionals. Laboratory professionals must recognize unreliable results, determine the possible cause(s), and be acquainted with the ways to obtain reliable results on such specimens. We present a concise overview of the known causes of unreliable automated CBC results, ways to recognize them, and means commonly utilized to obtain reliable results. Some examples of unreliable automated CBC results are also illustrated. Pertinent analyzer-specific information can be found in the manufacturers’ operating manuals.

  • 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]

Journal Information March, 2023
Vol.43 No.2
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