• 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.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.89-95
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• 1997

The authors studied 5 cases of idiopathic CNS hypersomnia who visited Division of Sleep Studies, Seoul National University Hospital in 1995. Detailed medical history was taken and nocturnal polysomnography(NPSG), multiple sleep latency test(MSLT) and human leukocyte antigen(HLA) typing were performed. Neither cataplexy nor hypnagogic hallucination was reported in all cases and in NPSGs, there were tendencies of increased sleep period time and decreased slow wave sleep time. In MSLT, all the subjects showed average sleep latencies less than 8 minutes without sleep-onset rapid eye movement period(SOREMP). In HLA typing, some correlation between idiopathic CNS hypersomnia and HLA DR4 was observed. In contrast to previous reports, overall treatment response with methylphenidate was remarkable. Therefore, the authors suggest that patients suspected of idiopathic CNS hypersomnia be actively evaluated and treated with rather optimistic perspective.

• Korean Journal of Veterinary Service
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• v.32 no.2
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• pp.147-153
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• 2009

Salmonella species are the most important etiologic agents of food-borne acute gastroenteritis. The most common serotypes isolated from humans are Salmonella enterica serotype Typhimurium (S. Typhimurium) and S. Enteritidis. Traditional detection methods for Salmonella are based on cultures using selective media and characterization of suspicious colonies by biochemical and serological tests. These methods are generally time-consuming and not so highly sensitive. Recently, the polymerase chain reaction (PCR) has been used as a highly sensitive, specific, and rapid test for the presence of pathogenic bacteria. In this study, a multiplex PCR (m-PCR) was used to detect S. Typhimurium and S. Enteritidis. We selected m-PCR target genes, which were the spv (virulence plasmid specific for S. Enteritidis) and sefA (S. Enteritidis fimbrial antigen) genes, fliC (H1-i antigen specific for S. Typhimurium) and a randomly cloned sequence specific for the genus Salmonella. With m-PCR, random sequence was detected from all strains of Salmonella spp, spv and sefA were detected from all strains of S. Enteritidis (100%), and fliC was detected from all strains of S. Typhimurium (100%). This assay indicate that the specificity of the m-PCR make them potentially valuable tools for detection of S. Typhimurium and S. Enteritidis.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.9-14
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• 2021

Toxoplasma gondii seroprevalence have been rapidly increasing in some parts of Korea. We analyzed prevalence of anti-Toxoplasma gondii antibodies, using a rapid diagnostic test (RDT), in the sera of 552 residents in Ganghwagun, 661 ones in Cheorwon-gun, and 305 ones in Goseong-gun, Korea in 2019. IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), glutathione-S-transferase-linker-SAG1A, were applied to the sera. IgG seroprevalence was 28.1% in Ganghwa-gun, 19.5% in Cheorwon-gun and 35.7% in Goseong-gun. Odds ratios comparing Cheorwon vs Ganghwa was 0.63 (P=0.001) and Goesong versus Ganghwa was 1.47 (P=0.01) adjusting age and sex. Goseong had highest seroprevalence among the 3 counties both in crude rates and logistic regression. Although Cheorwon and Goseong are adjacent to the demilitarized zone (DMZ) in Korea, seroprevalence rate was much higher in Goseong. Further investigation on other DMZ-closed areas is necessary whether they have high prevalence rates compared to the other areas. T. gondii prevalence in Korea is still persists; proper health policy should be established.

• Analytical Science and Technology
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• v.17 no.3
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• pp.211-216
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• 2004

Commercial one-step rapid fecal occult blood (FOB) kit which was used as a screening test to detect traces of blood in stool samples was evaluated for the feasibility of the forensic identification of human blood. The sensitivity was determined and compared with the conventional Leucomalichite green (LMG) method. In addition, the specificity of the kit and the effects of various chemicals and environmental factors were examined. FOB kit was specific for human hemoglobin and more sensitive than LMG test (approximately 100 times). FOB kit showed positive band using at least 1,000,000-fold diluted human blood. The antigen was very stable regardless of storage temperature and boiling. The positive reaction was not affected by LMG and Luminol, the traditional tests for identification of bloodstain. As a results, FOB test kit could be effectively applied to identification of human blood at crime scene and crime laboratories.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.269-276
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• 2018

Rabies virus (RABV)-specific antibodies in animals and humans are measured using standard methods such as fluorescent antibody virus neutralization (FAVN) tests and rapid fluorescent focus inhibition tests, which are based on cell culture systems. An alternative assay that is safe and easy to perform is required for rapid sero-surveillance following mass vaccination of animals. Two purified monoclonal antibodies (4G36 and B2H17) against RABV were selected as capture and detection antibodies, respectively. A genetically modified RABV, the ERAGS strain, was propagated and concentrated by polyethylene glycol precipitation. Optimal conditions for the RABV antigen, antibodies, and serum dilution for a blocking enzymelinked immune sorbent assay (B-ELISA) were established. We evaluated the sensitivity, specificity, and accuracy of the B-ELISA using serum samples from 138 dogs, 71 raccoon dogs, and 25 cats. The B-ELISA showed a diagnostic sensitivity of 95.8-96.3%, specificity of 91.3-100%, and accuracy of 96.0-97.2% compared to the FAVN test. These results suggest that the B-ELISA is useful for sero-surveillance of RABV in dogs, raccoon dogs, and cats.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.247-254
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• 2017

ELISA has been used for the diagnosis of toxoplasmosis, but it is being gradually replaced by a rapid diagnostic test (RDT). We compared and analyzed ELISA and RDT results using the sera collected during 4 consecutive years from residents of Gyodong-do (Island), Incheon-city, Korea. Sera from 921, 993, 940, and 838 adult residents were collected on a yearly basis (2010-2013). ELISA was performed by using a crude extract of T. gondii RH strain antigen and IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A, were applied to the sera. Comparison between groups was analyzed by the Student's t-test. The positive seroprevalence surged from 14.7% (135/921, 2010), 23.1% (231/993, 2011), 23.6% (222/940, 2012), and 32.1% (269/838, 2013) by ELISA. In contrast, RDT showed a more moderate increasing trend from 21.7% (200/921, 2010), 25.5% (253/993, 2011), 28.9% (272/940, 2012) and 33.1% (277/838, 2013). Discrepancies between ELISA and RDT were noted near the cut-off value. At the OD 0.15-0.24 range, RDT could detect 16.1% (169/1051) more positives, which suggests an early or acute toxoplasmosis, but at the OD 0.25-0.34 range, ELISA could detect 35.9% (92/256) more positives of possible chronic infections. Over the OD > 0.35 ELISA and RDT agreed in the majority of the cases. This surge in seroprevalence may be caused by the organic agriculture in addition to eating behavior or increase in pets among Koreans. These facts may be applied on a full-scale national survey using RDT to supplement ELISA to define the characteristics of the infection.

• Korean Journal of Veterinary Pathology
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• v.1 no.2
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• pp.119-124
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• 1997

The objective of this study was to develop digoxigenin (DIG)-labeled in situ hybridization (ISH) test for diagnosis of Aujeszky's Disease(AD) in infected organs. Specific DNA with well conserved gene sequences encoding gp50 antigen in AD virus (ADV) was obtained by Polymerase Chain Reaction (PCR) method. A pair of oligonucleotide primers used in PCR allowed amplification of a 217 bp sequence from the gp50 ADV gene. The DNA was then labeled with DIG by primer labeling method for use as probe in ISH test to detect ADV nucleic acids in various tissue. Positive hybridization was demonstrated by dark pigmentation in nuclei and cytoplasm of ADV infected cells particularly in brain tonsillar crypt epithelium and pulmonary alveolar cells. This result suggests that ISH is a valuable sensitive and rapid diagnostic test for AD.

• Animal cells and systems
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• v.7 no.1
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• pp.89-92
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• 2003

Immunoassays have become indispensable tools and achieved great importance in scientific and medical research. However, typical immunoassays are time-consuming and use complex, multi-step procedures. In this study, we introduce a new immunoassay system for the quantification of several analytes at a time without any washing steps. It is comprised of a detector solution with fluorescence-labeled antibodies and a test strip with immobilized capture antibodies. Using a micro-array scanner, the antigen-antibody complex was quantitatively determined by measuring the intensities of fluorescence on the capture lines or dots of nitrocellulose membrane. This method demonstrated its rapid quantitative determination of analytes without many processing steps as well as specific identification of multiple analytes in biological specimens.

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.271-279
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• 1998

Background: Diagnosis by direct microscopy and/or by culture of the Mycobacterium tuberculosis from body fluids or biopsy specimens is "Gold standard". However, the sensitivity of direct microscopy after Ziehl-Neelsen staining is relatively low and culture of mycobacteria is time consuming. Detection of mycobacterial DNA in clinical samples by the polymerase chain reaction is highly sensitive but laborious and expensive. Therefore, rapid, sensitive and readily applicable new tests need to be developed. So we had evaluated the clinical significance of serologic detection of antibody to 38 kDa antigen, which is known as the most specific to the M. tuberculosis complex, and culture filtrate antigen by ELISA in sputum AFB smear negative patients. Method: In this study, culture tests for acid fast bacilli with sputa or bronchial washing fluids of 183 consecutive patients who were negative of sputum AFB smear were performed. Simultaneously serum antibodies to 38 kDa antigen and unheated culture filtrate of M. tuberculosis were detected by an ELISA method. Results: The optical densities of ELISA test with 38 kDa and culture filtrate antigen were significantly higher in active pulmonary tuberculosis cases than in non tuberculous pulmonary diseases (p<0.05), but in patients with active pulmonary tuberculosis, those of the sputum culture positive patients for M. tuberculosis were not significantly different from those of the sputum culture negative cases(p>0.05). In the smear-negative active pulmonary tuberculosis patients, the sensitivity of the ELISA using 38 kDa antigen and culture filtrate was 20.0% and 31.4%. respectively. The specificity was 95.3% and 93.9%. respectively. Conclusion : In active pulmonary tuberculosis but smear negative, the serologic detection of antibody to 38 kDa antigen and culture filtrate by ELISA cannot substitute traditional diagnostic tests and does not have clinically significant role to differenciate the patient with active pulmonary tuberculosis from other with non-tuberculous pulmonary diseases.