Negative conversion of T-SPOT results after hemodialysis: case series and literature review

Abstract Background Latent tuberculosis infection (LTBI) affects 11.9% of outpatients under maintenance hemodialysis in Japan. In addition, the risk of reactivation of LTBI in hemodialysis patients is up to 10–25 times higher than that in the general population. Therefore, the accurate diagnosis and treatment for LTBI are extremely important. The interferon-γ release assays are widely used for screening LTBI; however, the impact of hemodialysis on the assay results has been uncertain. Case presentation Twenty-seven hemodialysis patients (17 males, 69.9 ± 10.1 year old) were performed T-SPOT ® .TB test (T-SPOT) both before and after hemodialysis. In cases where T-SPOT results were different before and after hemodialysis, T-SPOT was re-evaluated in a same manner. As a result, two cases showed consistent T-SPOT diagnostic discrepancy before and after hemodialysis in two measurements. In the first case, T-SPOT was indeterminate/positive before hemodialysis, but changed to negative after hemodialysis. In the second case, T-SPOT was positive before hemodialysis, but changed to indeterminate after hemodialysis. Conclusions We experienced the negative conversion of T-SPOT after hemodialysis in cases of LTBI. T-SPOT may show false-negative when measured after hemodialysis due to immunomodulation caused by hemodialysis.