The value of interferon-gamma releasing assays (IGRA) determining latent tuberculosis infection in renal transplant candidates

Objectives: Tuberculosis(TB)has 20-75 times higher incidence among transpalnt patients. Latent tuberculosis infection(LTBI)is a condition that may progress to active TB.Tuberculin skin test(TST)and IGRA depend on the specific immune response to Mycobacterium tuberculosis. Immunosupression increases in end stage renal disease due to high urea levels, causing lymphocyte dysfunction.Detection of LTBI in renal transplant candidates (RTCs)is important because active TB is a preventable disease. The aim of our study is to investigate the factors that influence IGRAresults in RTCs. Methods: 202RTCs9 records were evaluated retrospectively. Chest X-rays, thorax computed tomographies were evaluated to detect thoracic sequelae of TB.TB exposure and TB diagnosis history were noted.RTCs with negative IGRAresults and positive thoracic sequelae of TB or/and history of TB or/and exposure of TB were noted as 9false negative9 IGRA. Results: IGRA results were 68,3% negative.When IGRA results evaluated with radiology and positive history or exposure of TB, 31 of the negative results were 9false negative9(15,3%).The relationship between smoking history and false negative results were significant(p=0,01). Packyears correlated with false negative results(rho=0,26 p=0).Lymphocyte counts negatively correlated with false negative IGRAs (rho=-0, 35 p=0). Conclusion: IGRA sensitivity is lower in renal failure patients.Smoking and lymphocyte count have roles in false negative results. There is not a gold standard test for LTBI but IGRA is known to be a better test than TST in immunocompromised patients. New tests are needed for exact detection of LTBI to prevent TB in transplant patients.