• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.284-295
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• 2020

In December 2019, the first coronavirus disease- 2019 (COVID-19) patient was reported in Wuhan, Hubei Province, China. Since then, the number of patients who suffered severe acute respiratory syndrome caused by the novel Coronavirus (SARS-CoV-2 or 2019-nCoV) has increased dramatically in Korea. This new variant virus induces pulmonary diseases, including cough, sore throat, rhinorrhea, dyspnea, and pneumonia. Because SARS-CoV-2 is an RNA virus, real-time reverse-transcriptase PCR has been used widely to diagnose COVID-19. As the Korea Centers for Disease Prevention and Control (KCDC) and Ministry of Food & Drug Safety (MFDS) approved emergency use authorization, clinical specimens collected from COVID-19 patients and even healthy people have been clinically diagnosed by laboratory medicine. Based on a literature search, this paper reviews the epidemiology, symptoms, molecular diagnostics approved by KCDC, a current diagnosis of COVID-19 in the laboratories, the difference between molecular and serological diagnosis, and guidelines for clinical specimens. In addition, the Korean guidelines of biosafety for clinical laboratory scientists are evaluated to prevent healthcare-associated infection. The author's experience and lessons as clinical laboratory scientists will provide valuable insights to protect the domestic and international health community in this COVID-19 pandemic around the world.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.1
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• pp.1-10
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• 2018

During early pregnancy, before the development of a functioning thyroid gland, thyroid stimulating hormone (TSH) is a very sensitive marker of thyroid dysfunction during pregnancy. Normal values have been modified during gestation with a downward shift. The fetus is influenced by the TSH supplied by the mother. TSH and free thyroxine (FT4) concentrations vary during pregnancy and conventional units can vary between laboratories. A downward shift of the TSH reference range occurs during pregnancy, with a decrease in both the lower and upper limits of maternal TSH, relative to the typical non-pregnant TSH reference range. Each laboratory produces its own reference TSH and FT4 concentrations because there are many different assays that yield different results in pregnancy. Therefore, automated immunoassays used for serum FT4 analysis are still used widely, but the important considerations discussed above must be noted. The use of population-based, trimester-specific reference ranges remains the best way to handle this issue The slight downward shift in the upper reference range of TSH occurring in the latter first trimester (7~12 weeks) of pregnancy, typically not observed prior to 7 weeks. Their use indicates high or low levels in a quantitative manner independent of the reference ranges. These data highlight the importance of calculating population-based pregnancy-specific thyroid parameter reference intervals. A precision medicine initiative in this area will require the collection and analysis of a large number of genetic, biological, psychosocial, and environmental variables in large cohorts of individuals. Large prospective randomized controlled trials will be needed to resolve these controversies.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.161-167
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• 2001

Purpose: Although gastric carcinomas occur throughout the world and the incidence is on the decrease, they remain the most common type of carcinoma in Korea. Significant advancements in the diagnostics and the surgical treatment of gastric carcinomas have been achieved during the last three decades. The present retrospective study was undertaken to investigate the chronological changes in the clinical features, including clinicopathological findings, operative treatment, and prognosis of gastric carcinomas. Materials and Methods: A total of 1973 patients with a primary gastric adenocarcinoma who had been treated surgically during the period from 1983 to 1998 at the Department of Surgery, Korea University College of Medicine, were divided into two groups to evaluate chronological changes: 1007 patients had been treated during the period from 1983 to 1992 (early period) and 966 patients during the period from 1993 to 1998 (late period). Chronological changes in age, sex, ratio of early gastric cancer (EGC), and resectability were analyzed in all 1973 cases. For the 1755 resected cases, we also studied the chronological changes in the clinicopathological and treatment factors between the early-period (n=894) and the late-period (n=867) groups. Results: There were significant differences between the two periods with regard to age and ratio of EGC: EGC was more frequent in the late period. Univariate analysis of resected cases showed that gross type, tumor size, depth of invasion, UICC stage, and histological type were statistically significant. The analysis of the treatment factors revealed that total gastrectomies and extended lymphadenectomies were more frequent during the late period. The number of lymph nodes dissected was $26.0\pm12.7$ in the early period and $33.4\pm14.1$ in the late period (p<0.01). The 5-year survival rate in all cases was $51.4\%$ in the early period and $55.9\%$ in the late period. The stage-related survival rates (UICC 4th Ed., 1987) in the early vs. the late periods were $92.9\%\;vs.\;95.5\%$ in stage IA, $82.1\%\;vs.\;91.1\%$ in stage IB, $76.5\%\;vs.\;73.1\%$ in stage II, $46.5\%\;vs.\;52.1\%$ in stage IIIA, $14.5\%\;vs.\;33.6\%$ in stage IIIB, and $2.8\%\;vs.\;8.8\%$ in stage IV. There was a statistically significant difference in survival between stage IIIB and IV. Conclusion: These results suggest that the differences in the clinicopathological findings are related primarily to the increased number of early gastric cancer cases in the late period and that the improved survival noted during the late period for in stage IIIB and IV cancers might be related to extended surgery.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.88-93
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• 2016

Dirofilaria immitis is a filarial nematode parasite that causes cardiopulmonary dirofilariasis in dogs. The purpose of this study was the development of real-time PCR assays for efficient detection of D. immitis. The D. immitis-specific primers confirmed in our previous study and a newly designed TaqMan probe were used for quantitative diagnostics. First, SYBR Green real-time PCR was performed using the specific primers and serially diluted genomic DNA or plasmid DNA, and melting curve analyses were performed after amplification. The melting curve showed one specific peak in each of the genomic and plasmid DNA reactions, suggesting that the primers specifically amplify the D. immitis cytochrome c oxidase subunit I gene. Comparison of SYBR Green and TaqMan real-time PCR using serially diluted plasmid DNA showed higher efficiency and specificity with TaqMan real-time PCR. The real-time PCR assays developed in this study will provide improved diagnostic methods to overcome the limitations of conventional diagnostic tools and facilitate more rapid and accurate diagnoses.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.3
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• pp.271-287
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• 2003

Statement of problem: Resonance frequency analysis (RFA) has been increasingly served as a non-invasive and objective method for clinical monitoring of implant stability. Many clinical studies must be required for standardized baseline data using RFA. Purpose: This study was performed to evaluate RFA value changes in two stage surgery group and one stage surgery group in patients. Material and method: Forty-seven mandibles in consecutively implant installed patients were selected for this study and 141 fixtures were installed. Ninety-three fixtures were double threaded, machined surface design ($Br{\aa}anemark^{(R)}$ MK III, Nobel Biocare AB, Goteborg, Sweden) and 48 fixtures were root form, threaded, HA-coated surface one ($Replace^{TM}$, Steri-Oss/Nobel Biocare AB, USA). Among those, each 10 fixture was installed in one stage group patients. ISQ values were measured using $Osstell^{TM}$ (Integration Diagnostics Ltd. Sweden) during fixture installation, at healing abutment connection and in the loading period for two stage surgery group patients and during at each 4, 6, 8, 10, 12week and in the loading phase for one stage surgery group patients and evaluated the changes according to the time and fixture type. Results: In two stage surgery group, mean and SO of ISQ values of machined surface implants were $76.85{\pm}3.74,\;75.76{\pm}5.04,\;75.73{\pm}4.41$ and those of HA-coated surface implant were $75.05{\pm}6.23,\;77.58{\pm}5.23,\;78.32{\pm}4.29$ during fixtures installation, at healing abutment connection and in the loading period, respectively. In one-stage surgery group, the ISQ values of machined surface and HA-coated surface implants decreased until 4 or 6 week and maintained at plateau for 1-3 week and increased to the loading period. Conclusions: Machined and HA-coated surface implants showed minimal ISQ changes with time if they were installed at the sites showing at least intact cortical plate and good bone qualities. And HA-coated implants had a tendency to show somewhat increased ISQ values with time.

• The Journal of Korean Medical History
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• v.32 no.2
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• pp.19-27
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• 2019

For the purpose of searching examination in the connection with clinical medicine and the basic theory of Korean Medicine, we comparatively studied on the physiological system of Hyun-Gok (1912~1987) and the Hyunsang system of Ji-San (1927~2000). The results are as follows. The metabolism of Yin and Yang is connected 'Gallbladder (膽)'-'Bladder (膀胱)' and Man (男), Woman (女), Old aged (老), Young child (小) style. Man and Woman are divided in the body form chacteristic not by the sex. 'Gallbladder (膽)'-'Bladder (膀胱)' style are divided in the body form chacteristic by the terms of Yin (陰) and Yang (陽). 'Gallbladder (膽)' style represents excessive Yang and deficient Yin, 'Bladder (膀胱)' style represents excessive Yin and deficient Yang. The four composition factor of the body is connected Material basis (精) type, Vital energy (氣) type, Mental faculties (神) type and Blood (血) type. In the diagnosis of body form on the Hyungsang Medicine, there are several types of body shape and categories of people. The Material basis (精) type, Vital energy (氣) type, Mental faculties (神) type and Blood (血) type are classified by the four composition factor of the body. The structural-mechanics organization of five Internal Organs (臟) is connected five Internal Organs (臟) types and the running-animal (走), bird (鳥), fish (魚), turtle (甲) types in the Hyunsang system. The five Internal Organs (臟) types are percived on the ears, eyes, nose, mouth and facial complexion. And the running-animal, bird, fish, turtle types are accorded to the individual personalities and the most-developed part in the body trunk by the Organ picture (藏象) theory. The six atmospheric influences (六氣) is connected the six Kyung types (六經形). The six Kyung types are regulated by the shape of eyes and nose representing for the relation of Vital energy (氣) and Blood (血). By the comparative study on the physiological system of Hyun-Gok and the Hyunsang system of Ji-San, we can search the connection with clinical medicine and the basic theory of Korean Medicine.

• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.578-584
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• 2018

Background: Accurate, rapid, and cost-effective screening tests for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection may be useful in laboratories that cannot afford automated chemiluminescent immunoassays (CLIAs). We evaluated the diagnostic performance of a novel rapid automated fluorescent lateral flow immunoassay (LFIA). Methods: A fluorescent LFIA using a small bench-top fluorescence reader, Automated Fluorescent Immunoassay System (AFIAS; Boditech Med Inc., Chuncheon, Korea), was developed for qualitative detection of hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), and antibody to HCV (anti-HCV) within 20 minutes. We compared the diagnostic performance of AFIAS with that of automated CLIAs-Elecsys (Roche Diagnostics GmbH, Penzberg, Germany) and ARCHITECT (Abbott Laboratories, Abbott Park, IL, USA)-using 20 seroconversion panels and 3,500 clinical serum samples. Results: Evaluation with the seroconversion panels demonstrated that AFIAS had adequate sensitivity for HBsAg and anti-HCV detection. From the clinical samples, AFIAS sensitivity and specificity were 99.8% and 99.3% for the HBsAg test, 100.0% and 100.0% for the anti-HBs test, and 98.8% and 99.1% for the anti-HCV test, respectively. Its agreement rates with the Elecsys HBsAg, anti-HBs, and anti-HCV detection assays were 99.4%, 100.0%, and 99.0%, respectively. AFIAS detected all samples with HBsAg genotypes A-F and H and anti-HCV genotypes 1, 1a, 1b, 2a, 2b, 4, and 6. Cross-reactivity with other infections was not observed. Conclusions: The AFIAS HBsAg, anti-HBs, and anti-HCV tests demonstrated diagnostic performance equivalent to current automated CLIAs. AFIAS could be used for a large-scale HBV or HCV screening in low-resource laboratories or low-to middle-income areas.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.1
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• pp.15-25
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• 2019

The development of reliable and objective definitions as well as automated processes for the detection of health care-associated infections (HAIs) is crucial; however, transformation to an automated surveillance system remains a challenge. Early outbreak identification usually requires clinicians who can recognize abnormal events as well as ongoing disease surveillance to determine the baseline rate of cases. The system screens the laboratory information system (LIS) data daily to detect candidates for health care-associated bloodstream infection (HABSI) according to well-defined detection rules. The system detects and reserves professional autonomy by requiring further confirmation. In addition, web-based HABSI surveillance and classification systems use discrete data elements obtained from the LIS, and the LIS-provided data correlates strongly with the conventional infection-control personnel surveillance system. The system was timely, acceptable, useful, and sensitive according to the prevention guidelines. The surveillance system is useful because it can help health care professionals better understand when and where the transmission of a wide range of potential pathogens may be occurring in a hospital. A national plan is needed to strengthen the main structures in HAI prevention, Healthcare Associated Prevention and Control Committee (HAIPCC), sterilization service (SS), microbiology laboratories, and hand hygiene resources, considering their impact on HAI prevention.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.3
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• pp.351-359
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• 2019

Neurocognitive testing commonly uses the MMSE (Mini-Mental State Examination) to evaluate the overall cognitive function of patients at outpatient clinics, but the MMSE has recently been extensively used in the SNSB II (Seoul Neuropsychological Screening Battery II) for making diagnoses. We retrospectively investigated the results of routine neurocognitive tests and the results of the blood tests of 120 elderly patients who had been referred to a South Central Medical Center from 2017 to 2018 and who had been examined at a public health center. These subjects' space-time capability was high on the sub-region of the global deterioration scale (GDS). GDS showed a significant increase as the Na decreased on the electrolyte analysis. The subjects' concentration, their language-based orientation for space and time, their memory, and their scores for the frontal lobe function on GDS showed statistically significant reductions (P<0.001) For the normal and abnormal groups according to the ALT and creatinine levels, the frontal/execute function areas showed statistically significant differences (P<0.001) as well as negative correlation between GDS and ALT (P<0.01). In conclusion, this study provides basic information to develop test items that are important for patient screening and diagnosis, and several routine blood chemistry factors provide basic information for diagnosing and assessing the status and progress of cognitively impaired patients.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.133-141
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• 2022

Candida is one of the most common causes of bloodstream infections and a leading cause of morbidity and mortality among hospitalized patients. The purpose of this study was to provide important information for formulating empirical treatment plans for candidemia by investigating the antifungal resistance rate of Candida. Among the Candida strains (973 cases) isolated from blood culture tests at the S hospital in 2009~2018, 4.7% (N=44) comprising the Candida spp. (932 strains) showed resistance to fluconazole. The resistant strains included C. albicans, C. parapsilosis, C. tropicalis, and C. glabrata. In addition Candida spp. (947 strains) showed resistance to amphotericin B (N=6, 0.6%), flucytosine (N=23, 2.4%) and voriconazole (N=24, 3.1%). C. albicans was resistant to fluconazole (N=23, 6.9%) and voriconazole (N=21, 6.0%), The statistical analysis showed that C. albicans and non-albicans Candida species were resistant to fluconazole (P=0.039) and voriconazole (P<0.001). A monitoring system to understand the rate of candidiasis infections in a hospital setting is required. It is also important to make the right choice of the antifungal agent based on drug susceptibility patterns. Therefore, an infection surveillance policy that tracks Candida resistance through regular antifungal susceptibility tests is necessary.