Analysis of factors lowering sensitivity of interferon-? release assay for tuberculosis.

ABSTRACT:

Background

Imperfect sensitivity of interferon-? 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.

SUBMITTER: Hang NT 

PROVIDER: S-EPMC3158775 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature