title: Predictive factors for indeterminate result on the QuantiFERON test in an intermediate tuberculosis-burden country.
abstract: OBJECTIVE
  The QuantiFERON-TB Gold In-Tube (QFT-G IT) test is based on the cellular immune response, and this assay can result in indeterminate results for the diagnosis of tuberculosis. The occurrence of indeterminate results may decrease the clinical usefulness of this test. Therefore, we investigated possible predictive factors that can influence the occurrence of indeterminate results from the QFT-G IT test.
  
  
  METHODS
  We conducted a case-control study with 162 case patients who had indeterminate results from a QFT-G IT test at a tertiary hospital in South Korea, from September 2006 to September 2009.
  
  
  RESULTS
  Of the 1276 patients, 162 (12.7%) cases that underwent QFT-G IT testing were reported as indeterminate results. Severe lymphopenia (odds ratio [OR] = 8.839; p < 0.001), chronic renal disease (OR = 2.838; p = 0.007), autoimmune disease (OR = 2.527; p = 0.017) and chronic lung disease (OR = 3.169; p = 0.007) were independent predictive factors for indeterminate results from a QFT-G IT test.
  
  
  CONCLUSIONS
  The patients with lower lymphocyte counts or immunosuppressive conditions showed a higher probability of indeterminate results from the QFT-G IT test. Careful attention to the pre-analytical conditions may be able to minimize this proportion.
authors.affiliation: Department of Internal Medicine and AIDS Research Institute, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Jeong
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Han
authors.forename: Chang Oh
authors.initials: CO
authors.lastname: Kim
authors.forename: Ji-Hyeon
authors.initials: JH
authors.lastname: Baek
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Jin
authors.forename: Nam Su
authors.initials: NS
authors.lastname: Ku
authors.forename: Jun Yong
authors.initials: JY
authors.lastname: Choi
authors.forename: Young Goo
authors.initials: YG
authors.lastname: Song
authors.forename: Hyon-Suk
authors.initials: HS
authors.lastname: Kim
authors.forename: June Myung
authors.initials: JM
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D019411:Clinical Laboratory Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D016867:Immunocompromised Host; D007371:Interferon-gamma / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D056910:Republic of Korea; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*
chemical_list: D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma