Letter to the Editor2022-03-01
Diagnostic Hematology
Hongkyung Kim 
, M.D., Hye Min Kim , M.D., Jin Ju Kim , M.D., Saeam Shin , M.D., Doh Yu Hwang , M.D., Seung-Tae Lee , M.D., and Jong Rak Choi , M.D.
Editorial2022-03-01
Young Jin Kim , M.D., Ph.D., Soo-Youn Lee , M.D., Ph.D., and Mina Hur , M.D., Ph.D.
Original Article2021-07-01
Clinical Chemistry
Tae-Dong Jeong , M.D., Ph.D., Eun-Jung Cho , M.D., Ph.D., Kyunghoon Lee , M.D., Ph.D., Woochang Lee , M.D., Ph.D., Yeo-Min Yun , M.D., Ph.D., Sail Chun , M.D., Ph.D., Junghan Song , M.D., Ph.D., and Won-Ki Min , M.D., Ph.D.
Abstract : Background: Accurate serum creatinine (Cr) concentration measurement is essential for evaluating kidney function. In 2011, the Korean Association of External Quality Assessment Service (KEQAS) launched an accuracy-based Cr proficiency testing (ABCr PT) survey. We analyzed long-term data of the KEQAS ABCr PT survey collected between 2011 and 2019 to assess recent trends in Cr assays in Korea. Methods: The ABCr PT survey including three commutable fresh-frozen serum samples was performed twice a year. The target Cr concentration was assigned using isotope-dilution mass spectrometry. We analyzed data obtained from the participating laboratories, calculated the yearly bias, and evaluated bias trends for the major reagents and instruments. Outliers were excluded from all analysis. Results: The mean percentage bias based on the total data of all participating laboratories was 10.8% in the 2011-A survey and 0.2% in 2019-B survey. Bias for the major reagents and instruments differed depending on the manufacturer. Enzymatic assays generally showed desirable bias ranging from –3.9% to 3.2% at all Cr concentrations and lower interlaboratory variability than non-enzymatic assays (enzymatic vs. non-enzymatic, 3.3%–7.2% vs. 6.3%–9.1%). Conclusions: Although the mean percentage bias of Cr assays tends to decrease over time, it is necessary to continuously strive to improve Cr assay accuracy, especially at low concentrations.
Original Article2022-03-01
Clinical Chemistry
Youngwon Nam , M.D., Joon Hee Lee , M.D., Sung Min Kim , M.T., Sun-Hee Jun , M.T., Sang Hoon Song , M.D., Ph.D., Kyunghoon Lee , M.D., and Junghan Song , M.D., Ph.D.
Abstract : Background: Results from laboratories using multiple instruments should be standardized or harmonized and comparability-verified for consistent quality control. We developed a simple frequent comparability verification methodology applicable to large healthcare centers using multiple clinical chemistry instruments from different manufacturers. Methods: Comparability of five clinical chemistry instruments (Beckman Coulter AU5800, Abbott Architect Ci16000, two Siemens Vista 1500, and Ortho Vitros 5600) was evaluated from 2015 to 2019 for 12 clinical chemistry measurements. Pooled residual patient samples were used for weekly verifications. Results from any instrument exceeding the allowable verification range versus the results from the comparative instrument (AU5800) were reported to clinicians after being multiplied by conversion factors that were determined via a linear regression equation obtained from simplified comparison. Results: Over the five-year study period, 432 weekly inter-instrument comparability verification results were obtained. Approximately 58% of results were converted due to non-comparable verification. Expected average absolute percent bias and percentage of non-comparable results for non-converted and converted results after conversion action were much lower than those for data measured before conversion action. The inter-instrument CV for both non-converted and converted results after conversion action was much lower than that for measured data before conversion action for all analytes. Conclusions: We maintained within-laboratory comparability of clinical chemistry tests from multiple instruments for five years using frequent low-labor periodic comparability verification methods from pooled residual sera. This methodology is applicable to large testing facilities using multiple instruments.
Letter to the Editor2021-11-01
Diagnostic Hematology
Jee Ah Kim , M.D., Hyun-Young Kim , M.D., Seok Jin Kim , M.D., Hee-Jin Kim , M.D., and Sun-Hee Kim , M.D.
Brief Communication2021-03-01
Clinical Microbiology
Yu Jeong Lee , M.T., Eun Jeong Won , M.D., Ph.D., Young-Chang Cho , Ph.D., Soo Hyun Kim , M.D., Ph.D., Myung Geun Shin , M.D., Ph.D., and Jong Hee Shin , M.D., Ph.D.
Abstract : Stool examination is the gold standard for the detection of intestinal parasites. We assessed the performance of a newly developed AVE-562 analyzer (AVE Science & Technology Co., Hunan, China) for the vision-based detection of eggs of Clonorchis sinensis—the most common intestinal parasite in Korea—in stool samples. In total, 30 stool samples with a high or low egg count or without eggs (as negative control samples) (N=10 each) were prepared and analyzed. The performance of the AVE-562 analyzer was compared with that of the formalin-ether concentration (FEC) method. The overall correct identification rate of the AVE-562 analyzer based on FEC results was 66.6%. The sensitivity, specificity, positive predictive value, and negative predictive value of the AVE-562 analyzer for detecting C. sinensis eggs were 36.4%, 100.0%, 100.0%, and 73.1%, respectively. The average time required to run five tests simultaneously was 27 min using the AVE-562 analyzer and 58 min using the FEC method. Although the AVE-562 analyzer enables rapid and convenient stool examination, its sensitivity needs to be improved, particularly considering the prevalence of low-burden C. sinensis infection in Korea.
Letter to the Editor2022-03-01
Diagnostic Hematology
Shinae Yu , M.D., Sae Am Song , M.D., Ph.D., Kyung Ran Jun , M.D., Ph.D., Ha Young Park , M.D., and Jeong Nyeo Lee , M.D., Ph.D.
Letter to the Editor2022-05-01
Clinical Microbiology
Sang Hyuk Park , M.D., Ph.D., Hyun-Ki Kim , M.D., Hang Kang , Ph.D., Jung Heon Kim , Ph.D., Jaeseung Lee , M.S., Ji-Hun Lim , M.D., Ph.D., Seon-Ho Lee , M.D., Ph.D., and Joseph Jeong , M.D., Ph.D.
Editorial2021-07-01
Sun Young Cho , M.D., Ph.D. and Mina Hur , M.D., Ph.D.
Original Article2022-03-01
Clinical Microbiology
Ju Yeong Kim , M.D., Ph.D., Myung-Hee Yi , Ph.D., Myungjun Kim , B.S., Joon-Sup Yeom , M.D., D.T.M.&H., Ph.D., Hyun Dong Yoo , M.D., Seong Min Kim , M.D., Ph.D., and Tai-Soon Yong , M.D., Ph.D.
Abstract : Background: Identifying the causal pathogen of encephalitis remains a clinical challenge. A 50-year-old man without a history of neurological disease was referred to our department for the evaluation of an intracranial lesion observed on brain magnetic resonance imaging (MRI) scans, and the pathology results suggested protozoal infection. We identified the species responsible for encephalitis using thymine–adenine (TA) cloning, suitable for routine clinical practice. Methods: We extracted DNA from a paraffin-embedded brain biopsy sample and performed TA cloning using two universal eukaryotic primers targeting the V4-5 and V9 regions of the 18S rRNA gene. The recombinant plasmids were extracted, and the inserted amplicons were identified by Sanger sequencing and a homology search of sequences in the National Center for Biotechnology Information Basic Local Alignment Search Tool. Results: The infection was confirmed to be caused by the free-living amoeba Balamuthia mandrillaris. Two of 41 colonies recombinant with 18S V4-5 primers and 35 of 63 colonies recombinant with the 18S V9 primer contained B. mandrillaris genes; all other colonies contained human genes. Pathogen-specific PCR ruled out Entamoeba histolytica, Naegleria fowleri, Acanthamoeba spp., and Toxoplasma gondii infections. Conclusions: This is the first report of B. mandrillaris-induced encephalitis in Korea based on molecular identification. TA cloning with the 18S rRNA gene is a feasible and affordable diagnostic tool for the detection of infectious agents of unknown etiology.
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