Interferon Gamma Release Assays (IGRA) Testing Versus Tuberculin Skin Test in Renal Transplant Recipients

In a recent study (Triverio PA et al. "Interferon-gamma release assays versus tuberculin skin testing for detection of latent tuberculosis in haemodialysis patients". Nephrol Dial Transplant 2009; 24: 1952-6), the investigators had compared 2 IGRAs (T-SPOT.TB and Quantiferon Gold) with the TST and shown that one IGRA was clearly more sensitive than the TST but that both tests had a very low sensitivity for detecting prior TB. This study applies the same protocol to renal transplant recipients undergoing routine annual check-up visits: questionnaire with detailed collection of risk factors for latent tuberculosis infection (LTBI), history of prior contact with tuberculosis (TB), BCG (Bacille of Calmette and Guerin vaccine), prior TB or LTBI, treatment for TB or LTBI, analysis of chest X-ray for signs of prior TB, on-going treatment, level of immunosuppression (CD4 lymphocytes), simultaneous blood sampling for T-SPOT.TB and Quantiferon Gold, and tuberculin skin testing.