It is estimated that about a third of the world's population is infected with bacillus Mycobacterium tuberculosis. Infection with this microorganism is specially dangerous for immunocompromised persons, in which the probability of latent form of TB progressing into the active form is 21-34 times greater than in immunocompetent individuals, and hence is the most common cause of death in HIV infected individuals. The aim of the research is to analyze the connection between immune status, estimated on the basis of the number of CD4+ T lymphocytes, and test results of quantification of IFN-γ in the supernatant of peripheral blood lymphocytes after stimulation with antigens of M. tuberculosis in vitro (QuantiFERON assay) which detects latent tuberculosis. The study was conducted on samples of peripheral blood of 783 patients, of which a total of 208 (26.6%) were infected with HIV. In the group of HIV-infected persons, QuantiFERON assay was positive in 31 of 208 (14.9%) individuals. 167 (80.3%) were negative. In 10 of 208 (1.2%) HIV-infected persons QuantiFERON assay result was indeterminate. In the control group, 173 (30%) were positive for TB, 364 (63.3%) negative, and in 37 patients (6.4%) in the control group QuantiFERON assay result was indeterminate. We found a correlation between the immune status and indeterminate results and therefore conclude that in HIV-infected people with extensive deficiency of cellular immunity necessary to perform QuantiFERON assay, it is necessary to implement other experimental methods for the diagnosis of latent tuberculosis and repeat testing after administration of antiretroviral therapy and consequently increased number of CD4+ T lymphocytes above 200 CD4+ T cells/μL.