Comparison of Quantiferon-TB Gold and TST tests in the diagnosis of latent tuberculosis infection among HIV infected patients in Hamadan, west of Iran.

INTRODUCTION

Human immunodeficiency virus (HIV) infection increases the susceptibility of patients for latent tuberculosis infection (LTBI) and reactivtion tuberculosis. This study aimed to compare the Quantiferon-TB gold-in tube test (QFT) with tuberculin skin test (TST) in the diagnosis of LTBI in HIV infected patients.

METHODOLOGY: This comparative study of 89 patients with HIV in the Behavioral Diseases Counseling Center in Hamadan was carried out from July 2015 to November 2016. After obtaining consent from the patients, all demographic data, clinical manifestations, and laboratory results (CD4 count, TST and QFT) were entered into the questionnaires. The CD4 count is usually routinely performed using flow cytometry at the Behavioral Counselling Center. Quantiferon-TB test was done by using Qiagen - Quantiferon-2 plate kit ELISA.

RESULTS

Totally, 89 HIV infected patients with the mean age of 39.55 ± 10.31 years old were enrolled in the study. Sixty patients (67.42%) were male. The mean duration of HIV infection was 4.44 ± 3.88 years and the mean of CD4 count was 388.65 ± 260.66 cells/µL . Twenty patients had LTBI based on TST. Considering the QFT intermediate results as a positive test, the percent agreement of QFT and TST was 59.55%, which was not statistically significant (P = 0.2387).

CONCLUSIONS

According to the results, there was no significant percent agreement between QFT and TST for detecting LTBI in HIV infected patients. However, by decreasing CD4 counts, there was a significant relation between TST positive and LTBI in HIV patients.