title: Analysis of factors lowering sensitivity of interferon-γ release assay for tuberculosis.
abstract: BACKGROUND
  Imperfect sensitivity of interferon-γ release assay (IGRA) is a potential problem to detect tuberculosis. We made a thorough investigation of the factors that can lead to false negativity of IGRA.
  
  
  METHODS
  We recruited 543 patients with new smear-positive pulmonary tuberculosis in Hanoi, Viet Nam. At diagnosis, peripheral blood was collected and IGRA (QuantiFERON-TB Gold In-Tube) was performed. Clinical and epidemiological information of the host and pathogen was collected. The test sensitivity was calculated and factors negatively influencing IGRA results were evaluated using a logistic regression model in 504 patients with culture-confirmed pulmonary tuberculosis.
  
  
  RESULTS
  The overall sensitivity of IGRA was 92.3% (95% CI, 89.6%-94.4%). The proportions of IGRA-negative and -indeterminate results were 4.8% (95% CI, 3.1%-7.0%) and 3.0% (95% CI, 1.7%-4.9%). Age increased by year, body mass index <16.0, HIV co-infection and the increased number of HLA-DRB1*0701 allele that patients bear showed significant associations with IGRA negativity (OR = 1.04 [95% CI, 1.01-1.07], 5.42 [1.48-19.79], 6.38 [1.78-22.92] and 5.09 [2.31-11.22], respectively). HIV co-infection and the same HLA allele were also associated with indeterminate results (OR = 99.59 [95% CI, 15.58-625.61] and 4.25 [1.27-14.16]).
  
  
  CONCLUSIONS
  Aging, emaciation, HIV co-infection and HLA genotype affected IGRA results. Assessment of these factors might contribute to a better understanding of the assay.
authors: NCGM-BMH Medical Collaboration Center, Hanoi, Viet Nam.
authors: Nguyen Thi Le
authors: NT
authors: Hang
authors: Luu Thi
authors: LT
authors: Lien
authors: Nobuyuki
authors: N
authors: Kobayashi
authors: Takuro
authors: T
authors: Shimbo
authors: Shinsaku
authors: S
authors: Sakurada
authors: Pham Huu
authors: PH
authors: Thuong
authors: Le Thi
authors: LT
authors: Hong
authors: Do Bang
authors: DB
authors: Tam
authors: Minako
authors: M
authors: Hijikata
authors: Ikumi
authors: I
authors: Matsushita
authors: Nguyen Van
authors: NV
authors: Hung
authors: Kazue
authors: K
authors: Higuchi
authors: Nobuyuki
authors: N
authors: Harada
authors: Naoto
authors: N
authors: Keicho
mesh_terms: D000328:Adult; D000367:Age Factors; D004614:Emaciation; D005260:Female; D015658:HIV Infections; D006680:HLA Antigens; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000592:standards*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*; D014744:Vietnam
chemical_list: D006680:HLA Antigens