The Korean Journal of Medicine

The Korean Association of Internal Medicine (대한내과학회)
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Comparison of the Diagnostic Usefulness of Two Whole-Blood Interferon-Gamma Assays for Extrapulmonary Tuberculosis

폐외 결핵 진단에서 2개의 전혈 인터페론 감마 측정법의 유용성 비교

  • Han, Song-Yee (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Lee, Hyuck (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Jung, Dong-Sik (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Kim, Kyeong-Hee (Department of Laboratory Medicine, Dong-A University College of Medicine) ;
  • Woo, Su-Mi (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Park, So-Young (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Seo, Jeong-Min (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Jung, Jin-Kyu (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Yoon, Neul-Bom (Department of Internal Medicine, Dong-A University College of Medicine) ;
  • Lee, Sung-Woo (Department of Internal Medicine, Dong-A University College of Medicine)
  • 한송이 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 이혁 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 정동식 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 김경희 (동아대학교 의과대학 진단검사의학교실) ;
  • 우수미 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 박소영 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 서정민 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 정진규 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 윤늘봄 (동아대학교 의과대학 내과학교실 감염내과) ;
  • 이성우 (동아대학교 의과대학 내과학교실 감염내과)
  • Published : 2011.10.01
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Abstract

Background/Aims: The QuantiFERON-TB Gold (QFT-G) and QuantiFERON-TB Gold in tube (QFT-IT) assays have been studied primarily for the use of diagnosing active pulmonary tuberculosis (TB) or latent TB. The clinical usefulness of these assays for the detection of active extrapulmonary (EP) TB has not been fully defined. The aim of this study was to compare the diagnostic value of these two interferon-gamma assays for EP-TB. Methods: From June 2007 to August 2010, we evaluated the usefulness of QFT-G (n = 56) and QFT-IT (n = 48) in patients (n = 104) with suspected EP-TB. The diagnostic sensitivity, specificity, postive predictive value (PPV), and negative predictive value (NPV) of QFT-G and QFT-IT, and the cut-off value of QFT-IT were analyzed. Results: EP-TB was diagnosed in 55 (53%) patients. The overall sensitivity, specificity, PPV, and NPV of the QFT-IT assay were 96%, 42%, 62%, and 91%, respectively, and those of the QFT-G test were 81%, 52%, 68%, and 68%, respectively. In subgroup analyses according to infection site, the sensitivity and NPV of QFT-IT were higher than those of QFT-G. Analysis confirmed that the manufacturer's recommended test cut-off value fell within our cut-off value range (0.30-0.45 IU/mL; 95.8% sensitivity, 41.7% specificity). Conclusions: The QFT-IT assay showed superior sensitivity and NPV, and equivalent specificity, as comparison with the QFT-G test for the detection of Mycobacterium tuberculosis infection. The logistic benefits of the QFT-IT test format should facilitate the diagnosis of EP-TB.

목적: QuantiFERON-TB GOLD (QFT-G)와 QuantiFERON-TB GOLD in tube (QFT-IT) 검사는 주로 활동성 폐결핵 또는 잠복결핵의 진단과 관련되어 연구되어져 왔으나, 폐외 결핵의 진단과 유용성은 아직 잘 밝혀지지 않은 상태이다. 본 연구는 폐외 결핵 환자에서 QFT-G와 QFT-IT의 진단적 유용성에 대해 비교 분석하였다. 방법: 2007년 6월부터 2010년 8월까지 임상적으로 폐외 결핵이 의심되어 QFT-G, QFT-IT 검사를 한 환자 각각 56명과 48명을 대상으로 하였다. QFT-G와 QFT-IT의 민감도, 특이도, 양성예측도, 음성예측도와 QFT-IT의 cut-off value를 통하여 진단적 유용성을 분석하였다. 결과: 폐외 결핵으로 진단된 환자는 55명(53%)이었고 QFT-IT의 민감도, 특이도, 양성예측도, 음성예측도는 96%, 42%, 62%, 91%이었으며, QFT-G는 81%, 52%, 68%, 68%이었다. 감염 부위에 따른 검사 결과 또한 민감도, 음성예측도에서 QFT-IT가 QFT-G보다 더 높은 결과를 보였다. 본 연구에서 cut-off value는 기존에 권고하고 있는 cut-off value의 범위 안에 포함되었다(0.30-0.45 IU/mL, sensitivity 95.8%, specificity 41.7%). 결론: QFT-IT는 M.tuberculosis 감염의 진단에 있어서 QFT-G보다 높은 민감도와 음성예측도를 보이며, 특이도에 있어서는 유사한 결과를 보여 새로운 IGRA방법으로서 폐외결핵의 진단을 더 강화시킬 수 있는 가능성을 보여주었다.

Keywords

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