Feasibility of the Interferon-γ Release Assay for the Diagnosis of Genitourinary Tuberculosis in an Endemic Area

PURPOSE To evaluate the feasibility of the interferon-gamma release assay (IGRA) as a supplementary diagnostic tool for the diagnosis of genitourinary tuberculosis (GUTB). MATERIALS AND METHODS Fifty-seven patients who were tested with the IGRA to diagnose GUTB were included. All patients had clinical or radiologic features suspicious for GUTB. Signs and symptoms included chronic dysuria with long-standing sterile pyuria, renal calcification with distorted renal calyces and contracted renal pelvis, and chronic epididymitis. Patients who had a history of tuberculosis in other organs were excluded. Tests including IGRA, urine acid-fast bacilli (AFB) stain and culture, urine tuberculosis polymerase chain reaction (UT-PCR), and radiological examinations were performed to confirm GUTB. The medical records of the patients were reviewed retrospectively. RESULTS The IGRA result was positive in 30 patients (52.6%). The results of the urine AFB stain and culture were positive in 5 patients (8.8%) and 7 patients (12.2%), respectively. The results of UT-PCR were positive in 9 patients (15.8%). The 7 patients who showed positive results in the urine AFB stain and culture also had positive results on the IGRA. A UT-PCR-negative patient was diagnosed with GUTB by positive results on both the IGRA and AFB stain and culture. CONCLUSIONS The IGRA might feasibly be used as a supplementary or screening tool for the diagnosis of GUTB in addition to urine AFB stain and culture. Further studies for statistical evaluation of its sensitivity, specificity, and efficacy are needed.