• 제목/요약/키워드: False positive reactions

검색결과 20건 처리시간 0.029초

Acidic hydrogen peroxide로 혈액을 증강할 때의 위양성 및 위음성 반응 (False positive and false negative reactions of acidic hydrogen peroxide for enhancing blood)

  • 이원영;홍성욱
    • 분석과학
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    • 제35권3호
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    • pp.124-128
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    • 2022
  • 혈액을 증강하기 위해 사용하는 시약은 혈액 이외의 다른 물질의 영향을 받아 위양성 혹은 위음성을 나타낼 수 있다. 이런 반응이 일어나면 혈액 증거를 잘못 해석할 수 있으므로 혈흔 증강 시약의 위양성 및 위음성 가능성에 대한 조사는 필수적이다. 산성 과산화수소(acidic hydrogen peroxide, AHP)는 최근에 알려진 혈액 증강 시약으로, 위양성 혹은 위음성을 유발하는지에 대해 알려진 바가 없다. 이를 확인하기 위해 금속 표면, 플라스틱 표면, 종이 표면, 페인트 표면, 음식류, 식물성 기름, 세제류, 석유계 탄화수소에 혈액 20 µL을 남긴 후 AHP를 처리하였다. 이 혈액을 505 nm 광원을 비추며 오렌지색 필터를 통해 관찰 한 결과 모든 물질에서 위양성 혹은 위음성 반응이 관찰되지 않았다. 그러나 polyethylene terephthalate 표면, polyvinylchloride 표면, 일부 페인트 표면, 음식류는 AHP를 처리한 혈액 관찰 조건에서 자체 광발광을 나타내 혈액 관찰을 방해한다는 점을 확인할 수 있었다.

Clearance of False-positive Antigen-Antibody Reactions of a Diagnostic Antigen Production in Escherichia coli with Human Sera

  • Noh, Kap-Soo;Kim, Jong-Wan;Ha, Suk-Hoon;Yoo, Wang-Don;Jeon, Weong-Joong;Kim, Hyun-Su
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제4권1호
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    • pp.63-65
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    • 1999
  • Although many pharmaceutically useful proteins are produced in E. coli expression system, it is very are rare for the system to be used in the production of diagnostic antigen due to a major problem, i.e., false-positive reaction of e. coli host-derived proteins contaminating purified diagnostic antigen with human sera. The N (nucleocapsid) protein of Seoul virus causing haemorrhagic fever with renal syndrome (HFRS) was produced in E. coli BL21 (DE3), and used for the detection of N protein-specific antibodies in human sera. Using the N protein as a diagnostic antigen of HFRS, the false-positive reaction was cleared by merely mixing the test sera with the extract of E. coli host strain not harboring expression plasmid.

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브루셀라병(病) 검색(檢索)에 사용(使用)되는 여러가지 혈청진단법(血淸診斷法)의 비교연구(比較硏究) (Comaprison of Six Serological Methods for the Diagnesis of Bovine Brucellosis)

  • 김금화;안수환;박용호;김동성
    • 대한수의학회지
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    • 제22권2호
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    • pp.149-153
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    • 1982
  • Results obtained from six secological tests for diagnosing bovine brucellosis-standard plate agglutination test (SPT), standard tube agglutination test(STT), complement fixation test(CFT), Rivanol test (RT), agar gel precipitation test (AGP) and counterimmunoelectrophoresis(CIEP) were compared using 38 sera from brucella reactors and 222 sera from dairy and beef cattle in field. The SPT gave 1.6% apparent false negative reactions and 15.4% apparent false positive reactions when compared with STT which is an official test for bovine brucellosis in this country. The distribution of antibody titers determined by STT showed that 37.5% of 38 reactors had antibody titers ranging from 100 to 200, and the remaining 62.5% had antibody titers of 400 or higher. when 38 reactor judged by STT were tested by CFT and RT, 32 cattle(82.4%) were positive by CFT and 33 cattle (86.8%) were positive by RT, respectively. This results suggest that RT is comparable to CFT in the diagnosis of bovine brucellosis. The results also indicated that both AGP and CIEP were insensitive to detect brucella infection in cattle.

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Protease antigen recovery의 B-Cell에 대한 비특이반응 유발 (Protease antigen recovery induces non-specific reaction in B-Cells)

  • 김옥진;이성준
    • 한국수의병리학회지
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    • 제7권1호
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    • pp.11-15
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    • 2003
  • Antigen retrieval (AR) techniques were widely used to recover the antigenicity from the fixed tissues, which were guided by the philosophy of rendering immunohistochemistry (IHC) applicable to routine formalin-fixed, paraffin-embedded tissues for wide application of IHC in research and clinical filed for morphological observation like as anatomy, histology and pathology. Protease antigen recovery (PAR) is an AR technique, which is obtained the antigen retrieve by using enzyme digestion, and commonly used in IHC field. However, during the IHC for the detection of ovine herpesvirus 2 (OvHV-2) antigen, we noted lymphocyte-like cells-specific staining in the infiltrated cells into various organs like as liver and kidney, which was also shown in the IHC tissues with isotype control. However, those signals were not observed in the tissues conducted with in situ hybridization. Therefore, we analyzed the specificity of the IHC detection results. We found that PAR may induce false-positive result during IHC in lymphocyte-like cells, which were infiltrated mainly around vessels and in interstitial tissues. Through the Phenotyping, we realized that those false-positive cells were B-cell-related cells. These results suggest that PAR, a AR using protease, may induce non-specific false-positive reactions during IHC.

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신생아 로타바이러스 감염 진단에서 효소면역법과 중합효소연쇄반응과의 비교 (Comparison of Enzyme-linked Immunosorbent Assay with Reverse Transcription-polymerase Chain Reaction for Identification of Rotavirus in Neonates)

  • 김성은;김미옥;박선영;정원조;마상혁;김윤정;김선주
    • Pediatric Infection and Vaccine
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    • 제7권1호
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    • pp.113-119
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    • 2000
  • Purpose : Rotavirus is a most common etiologic agent of pediatric gastroenteritis. The standard method to diagnose rotavirus infection was the detection of viral particles in specimens through electron microscopy. But it was complex. Enzyme immunoassay and latex agglutinin are preferred because they are relatively handy, inexpensive and take a short time, in comparison with electron microscopy. However, several reports have shown that the use of ELISA to diagnose rotavirus infection in neonates can result in false positive reactions. The main purpose of this study is to compare ELISA and RT-PCR in the diagnosis of neonatal rotavirus infection. Methods : Data presented in this study were obtained form 123 newborn babies in the nursery of the Fatima Hospital, Masan, Korea, form Jury to December, 1997. We obtained two samples of stool from each of the newborn babies and then performed the Rotazyme test and the RT-PCR. In the Rotazyme test, the results were interpreted according to visual findings. The samples were used for the RT-PCR test after at stock $-30^{\circ}C$ to identify rotavirus group A. The result of the two tests were compared. Results : The informations are divided into 73 males and females. Out of the total informations 15 were transferred from other hospitals. Their average gestational age was $38.5{\pm}1.6$ weeks. The average birth weight was $3134.8{\pm}539gm$. In the Rotazyme test, 75 samples turned out to be positive. Out of them, 55 samples(75.3%) were positive and 18 samples(24.7%) were negative in the RT-PCR. On the other hand, in the Rotazyme test, 50 samples turned out be negative. Out of them, 27 samples(54%) were positive and 23 samples(46%) were negative in the RT-PCR. Conclusion : Rotavirus infection in uncommon in neonates. The diagnosis based on visual findings using Rotazyme test has a disadvantage in the sense that it can result in false positive reactions and false negative reactions in the diagnosis of neonatal rotavirus infection.

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Evaluation of the EF-18 Agar-Hydrophobic Grid Membrane Filter (HGMF) Method to Isolate Salmonella from Poultry Products

  • Rosa Capita;Astorga, Maite-Alvarez;Calleja, Carlos-Alonso;Maria del Camino;Garcia-Fernandez;Benito Moreno
    • Journal of Microbiology
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    • 제39권3호
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    • pp.202-205
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    • 2001
  • The EF-18 agar/hydrophobic grid membrane filter (EF18/HGMF) method was evaluated for the isolation of Salmonella in naturally contaminated chicken carcasses, chicken parts (legs, wings and giblets) and processed chicken products (sausages and hamburgers). Percentages of false positive results for Salmonella (colonies with a similar morphology to those of Salmonella) were 78.75, 81.67 and 80% for carcasses, chicken parts and processed chicken products, respectively. The bacterial isolates that caused false positive reactions using this method were identified as Proteus mirabilis (70.85%), Citrobacter freundii (15.25%), Klebsiella ozaenae (5.83%), Hafnia alvei (4.48%), Escherichia coli (2.69%) and Enterobacter aerogenes (0.90%). The data obtained in this study suggest that the EF-18/HGMF method is not sufficiently selective or specific far isolating Salmonella from meat and chicken products.

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요검사: 요시험지봉 검사의 유용성과 한계 (Urinalysis: The Usefulness and Limitations of Urine Dipstick Testing)

  • 한태희
    • Childhood Kidney Diseases
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    • 제17권2호
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    • pp.42-48
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    • 2013
  • 소변검사는 신장질환과 기타전신질환의 진단에 매우 중요한 검사이다. 요시험지봉검사을 이용하면 짧은 시간에 소변의 여러 가지 화학 성상(pH, 비중, 단백, 당, 케톤체, 잠혈, 빌리루빈, 우로빌리노겐, 아질산염, 백혈구-에스테라제)을 동시에 검사할 수 있다. 요시험지봉검사는 관련된 화학반응이 복잡하여 소변에 존재하는 산화물질, 환원물질, 착색물질의 영향을 받을 수 있어 위양성 위음성 반응이 흔히 발생한다. 요시험지봉검사로 신뢰할 수 있는 결과를 얻기 위해서는 검체를 깨끗하게 채집하고 주의를 기울여 검사해야 하며 요시험지봉검사 결과를 제대로 이용하기 위해서는 검사의 원리를 잘 이해할 필요가 있다. 요시험지봉검사에서 혈뇨, 단백뇨, 요로감염이 의심되면 확진을 위해 요검경검사를 실시하여야 한다.

코로나19 백신 관련 영상의 특성 및 이용자 반응에 대한 연구 (Study on Characteristics and User Reactions of Videos Related to COVID-19 Vaccine)

  • 이미나;홍주현
    • 문화기술의 융합
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    • 제7권3호
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    • pp.163-171
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    • 2021
  • 이 연구는 코로나19가 야기한 인포데믹 상황에서 유튜브상에서 확산된 코로나19 백신 관련 영상의 주요 특성과 이용자 반응의 차이를 알아보고자 하였다. 코로나19 백신 관련 영상 579개에 대한 내용분석 결과, 허위정보는 모두 개인 채널이 저자인 것으로 나타났으며, 기관 및 단체, 언론사, 정부 채널에서는 사실 중심 보도와 더불어 허위정보에 대한 보도도 한 축을 이룬 것으로 나타났다. 진보 성향의 채널은 백신 접종을 찬성하는 긍정적 정서의 비율이 높았고, 보수 성향의 채널은 백신 접종에 반대하는 부정적 정서의 비율이 높았다. 백신 접종이 시작된 이후에 정부 채널의 영상이 증가했고, 긍정적 정서의 영상이 증가한 것으로 나타났다. 좋아요 수에 영향을 미치는 영상의 특성 요인을 회귀분석을 통해 알아본 결과, 개인 전문가 영상, 진보 성향 채널의 영상이 좋아요를 더 많이 받은 것으로 나타났다. 연구 결과를 종합하여 소셜미디어를 활용한 코로나19 백신 관련 정부 정책 홍보 방안에 대해 제시하였다.

Development of PCR Assay for Identification of Buffalo Meat

  • Rajapaksha, W.R.A.K.J.S.;Thilakaratne, I.D.S.I.P.;Chandrasiri, A.D.N.;Niroshan, T.D.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권7호
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    • pp.1046-1048
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    • 2003
  • A polymerase chain reaction (PCR) assay was developed to differentiate buffalo meat from the meat of Ceylon spotted deer (Axis axis ceylonensis), Ceylon sambhur (Cervus unicolor unicolor), cattle (Bovine), goat (Caprine), pig (Porcine), and sheep (Ovine). A set of primers were designed according to the sequence of the mitochondrial cytochrome b gene of bubalus bubalis and by PCR amplification a band of approximately 242 bp band was observed with buffalo DNA. These primers did not cross-react with DNA of other animal species tested in the study under the specified reaction conditions. A band of 649 bp was observed for all animal species tested when DNA was amplified with the universal primers indicating the presence of mitochondrial DNA in the samples. The technique was sensitive enough to identify rotten (10 days post slaughter), dried and cooked buffalo meat. The absence of a cross reaction with human DNA using the buffalo specific primers eliminates possible false positive reactions.

One Lambda LABTypeTM을 이용한 HLA- DR Typing시 나타나는 위양성과 위음성, High-Background 사례와 검사실 습도의 관계분석 (Association between False Positive, False Negative, High-Background Cases and Humidity in One Lambda LABTypeTM HLA-DR Typing)

  • 안향선;손민성
    • 대한임상검사과학회지
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    • 제55권3호
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    • pp.132-142
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    • 2023
  • 서울대학교병원 진단면역검사실에서 HLA 형별 검사를 위한 결과 산출하는 과정에서 HLA-DR 검사 시행 건수 총 611건 중 Lot No.20의 시약에서 빈번히 나타나는 위양성과 위음성으로 의심되는 특이 bead 들의 반응을 발견하게 되었다. 따라서 정확한 결과 산출과정을 모색하기 위하여 특이 bead들의 cut-off 수정을 하지 않은 검사결과 533건과 특이 bead의 cut-off 수정을 한 뒤 결과 산출을 한 78건의 사례들을 가지고 cut-off 수정을 야기시키는 요인을 여러 변수로서 규명하고자 하였다. 검체대상의 인구통계특성과 cut-off 수정 여부를 확인하기 위해 빈도분석, 검사실의 습도를 변수로 넣어 기술통계를 진행하였고, cut-off 수정 여부와 인구통계특성의 연관성을 확인하기 위하여 교차분석을 시행, cut-off 수정 여부에 따른 습도의 차이를 검증하기 위해 독립표본 t검증을 실시하였다. 마지막으로 습도수준에 따른 cut-off 수정비율의 관계를 검증하기 위해 로지스틱 회귀분석을 실시하였다. 결과적으로 검사실의 습도 수준이 증가함에 따라 cut-off 수정사례는 0.986배 감소하는 것으로 나타났다. 이는 습도가 낮아질수록 cut-off 수정률이 증가한다는 것을 의미한다. 따라서 검사실의 습도 또한 HLA typing 결과에 영향을 미치는 요인임을 시사한다.