Multiple Skin Colored Nodules on both Legs in Patient with Positive QuantiFERON®-TB Gold Test

Nodular tuberculid (NT) was originally described by Jordaan et al. in 2000 in 4 patients from South Africa. It appeared as nodules on the legs; the pathologic changes were situated in the deep dermis and adjacent subcutaneous fat. A 34-year-old woman visited our hospital with subcutaneous skin-colored or slightly erythematous round to oval nodules. Skin biopsies revealed granulomatous inflammation at the dermo-subcutaneous junction with vasculitis. Chest X-ray, tuberculosus (TB)-polymerase chain reaction and TB culture of the skin specimen were normal. A QuantiFERON®-TB Gold test (QUIAGEN, Germany) was positive, which suggested a diagnosis of latent TB infection. The patient was treated with anti-TB medication and her condition has not recurred. Herein, we report a case of a patient with latent TB diagnosed by a positive QuantiFERON®-TB Gold test whose skin lesions had the clinical and histopathologic features of NT.

Multiple Skin Colored Nodules on both Legs in Patient with Positive QuantiFERON®-TB Gold Test

Nodular tuberculid (NT) was originally described by Jordaan et al. in 2000 in 4 patients from South Africa. It appeared as nodules on the legs; the pathologic changes were situated in the deep dermis and adjacent subcutaneous fat. A 34-year-old woman visited our hospital with subcutaneous skin-colored or slightly erythematous round to oval nodules. Skin biopsies revealed granulomatous inflammation at the dermo-subcutaneous junction with vasculitis. Chest X-ray, tuberculosus (TB)-polymerase chain reaction and TB culture of the skin specimen were normal. A QuantiFERON®-TB Gold test (QUIAGEN, Germany) was positive, which suggested a diagnosis of latent TB infection. The patient was treated with anti-TB medication and her condition has not recurred. Herein, we report a case of a patient with latent TB diagnosed by a positive QuantiFERON®-TB Gold test whose skin lesions had the clinical and histopathologic features of NT.

Comparison of interferon gamma release assay & tuberculin skin tests for diagnosis of latent tuberculosis in patients on maintenance haemodialysis.

Background & objectives: Tuberculosis (TB) is a common infection in patients on haemodialysis. There is a definite role of treatment of latent TB (LTB) in these patients. However, diagnosis of LTB in these patients by tuberculin skin test (TST) is unreliable. There is suggestion that interferon gamma release assay (IGRA) will be more reliable test for diagnosis of LTB in this setting. Thus, we evaluated value of IGRA and TST for the diagnosis of LTB in patients on dialysis in an Indian setting. Methods: Patients with end stage kidney disease on dialysis were included. Patients with active TB were excluded. Each patient was subjected to TST (induration of ≥10 mm was taken as positive) and QuantiFERON TB Gold In-Tube test (QFT-GIT) for diagnosis of LTB. Results: A total of 185 patients were included; 129 (69.7%) were males and mean age was 36.7 ± 12.3 yr. Past history of TB was present in 18 (9.7%) patients. One hundred and thirty four (72.4%) patients had scar of BCG vaccination. QFT-GIT test was positive in 66 (36%), TST in 32 (17%) and both in 13 (7%) patients. Of the 66 patients positive with QFT-GIT, only 13 (19.6%) were positive for TST. Of the 32 patients positive with TST, only 13 (40.6%) were positive with QFT-GIT; 100 (54%) patients were negative for both the tests. Overall, 85 (45.9%) patients were positive for either of the two tests. Poor agreement was shown between the two methods. On logistic regression analysis, odds of QFT-GIT to be positive in patients with BCG vaccination was 1.23 and with history of TB 0.99, both being insignificant. odds of tuberculin skin test to be positive in patients with BCG vaccination was 1.04 and with history of TB 0.99, both again being insignificant. Interpretation & conclusions: Our findings showed that more number of patients (36%) on haemodialysis were positive for QuantiFERON Gold In-Tube test as compared to TST (17%). There was poor agreement between the two tests. no significant effect of BCG vaccination and history of TB in past was observed on both tests.

Poor agreement between QuantiFERON-TB Gold test and tuberculin skin test results for the diagnosis of latent tuberculosis infection in rheumatoid arthritis patients and healthy controls

BACKGROUND/AIMS: We investigated the agreement between the QuantiFERON-TB Gold (QFT-Gold) test and the tuberculin skin test (TST) in the diagnosis of latent tuberculosis infection in patients with rheumatoid arthritis (RA), compared with healthy controls, in Korea. METHODS: We recruited 64 patients with RA and 79 healthy controls at two university hospitals in South Korea. The participants underwent both the QFT-Gold test and the TST simultaneously between August 2006 and February 2009. All patients were diagnosed using the classification criteria for RA revised in 1987 by the American College of Rheumatology. Bacillus Calmette-Guerin vaccination status and current medications were evaluated, and disease activities were assessed using the Disease Activity Score in 28 joints. Eleven patients with RA produced indeterminate QFT-Gold test results and were thus excluded from the kappa analysis. RESULTS: Based on an induration of 10 mm in diameter as the TST cutoff value, the QFT-Gold test and TST demonstrated 75.0% agreement (kappa = 0.23) in patients with RA and 75.9% agreement (kappa = 0.19) in healthy controls. Among the 56 patients with RA who had negative TST results, 11 patients (17.2%) also yielded indeterminate QFT-Gold results. CONCLUSIONS: Our study showed poor agreement between the results of the QFT-Gold test and the TST in both RA patients and healthy controls. Based on these findings, we emphasize the importance of making clinical decisions in the diagnosis of latent tuberculosis in Koreans with or without RA.

Utility of QuantiFERON TB gold test in a south Indian patient population of ocular inflammation.

Aim: To study the utility of interferon-γ release assays (QuantiFERON TB gold test) in a south Indian patient population of intraocular inflammation. Design: Evaluation of a diagnostic test- a pilot study from January 2007 to October 2008. Materials and Methods: QuantiFERON TB gold test was performed on the following groups of patients following an informed consent. Group A included healthy volunteers without any exposure to tuberculosis (TB) or past history of TB (n=22). Group B included patients with active systemic TB diagnosed by the demonstration of acid-fast bacilli or by the histopathology finding of caseation with granuloma formation from the sputum, lymph node, skin or intestinal biopsies (n=26). Group C included patients with uveitis of known etiologies other than intraocular TB without any history of exposure to active TB (n=21). Group D included patients with a diagnosis of presumed intraocular TB, who responded to antitubercular therapy by decreased or no recurrences following treatment and with a minimum of nine months follow-up following initiation of antitubercular therapy (n=39). Results: The sensitivity and specificity of the QuantiFERON TB gold test to pick up active systemic TB was 58% and 77% respectively. The sensitivity and specificity of the QuantiFERON TB gold test to pickup intraocular TB was 82% and 76% respectively. Conclusions: QuantiFERON TB gold test alone may not be specific for intraocular TB. The significance of this test in a case scenario needs to be interpreted with clinical presentation and other evidences for intraocular TB.