Clinical evaluation of QuantiFERON TB-2G test for immunocompromised patients

Abstract

The usefulness of the tuberculin skin test (TST) and the QuantiFERON TB-2G (QFT-TB) test were compared in immunocompromised patients.The subjects consisted of 252 immunocompromised patients who were clinically suspected of tuberculosis (TB) infection between April 2005 and December 2006.Regarding the underlying diseases, 74 subjects had malignant diseases, 72 were undergoing immunosuppressive treatment, 52 had diabetes mellitus, 50 had chronic renal failure and four had HIV infection. While the positive rate of the QFT-TB test for the diagnosis of TB infection (TB disease or latent TB infection) was 78.1%, that of TST for TB infection was 50.0%. The QFT-TB test was significantly better than TST. However, 32 (13%) patients had an indeterminate QFT-TB result. Indeterminate findings were significantly more frequent in patients receiving immunosuppressive treatment (28%), especially with lymphocytopaenia in the peripheral blood, than in those who had other underlying diseases. While TST-positive and QFT-TB test-negative results were recognised in immunocompromised patients with bacille Calmette-Guérin vaccination or nontuberculous mycobacterial disease, TST-negative and QFT-TB test-positive results were recognised in immunocompromised patients with a past history of TB infection.It was concluded that the QuantiFERON TB-2G test is a more useful diagnostic method for tuberculosis infection than tuberculin skin test for immunocompromised patients suspected of tuberculosis disease. However, because the results of the QuantiFERON TB-2G test show an indeterminate response for patients receiving immunosuppressive treatment, especially for those with lymphocytopaenia due to severe underlying diseases, care must be taken in the interpretation of the QuantiFERON TB-2G test for these patients.

Active Tuberculosis in Patients Undergoing Hemodialysis for End-stage Renal Disease: A 9-year Retrospective Analysis in a Single Center

“…However, making a diagnosis tends to be difficult and delayed since patients commonly present with extrapulmonary involvement and nonspecific symptoms mimicking uremia (6,7). To date, few research groups have applied QuantiFERON TB-2G (QFT-2G) (Cellestis Ltd., Carnegie, Victoria, Australia) a diagnostic test for tuberculosis using Mycobacterium tuberculosisspecific antigens, early secreted antigenic target , and culture filtrate protein for dialysis patients (8). Furthermore, a previous study reported a lack of health-care facilities for such patients in Japan (9).…”

Extrapulmonary tuberculosis presented as fever of unknown origin in two patients with endstage kidney disease not on dialysis: usefulness of 18-FDG-PET/CT in the diagnostic localization of fever of unknown origin

“…A tuberculin skin test, which is often used in the general population, is less useful in hemodialysis patients because impaired cellular immunity yields a high prevalence of false-negative results [3][4][5]. The principle behind IGRA is to quantitatively assess activation of monocytes by measuring the amount of interferon-gamma released from CD4-positive lymphocytes exposed to specific antigens that are related to Mycobacterium tuberculosis: early secreted antigen target 6 and culture filtrate protein 10 [14]. Importantly, IGRA does not respond to other mycobacterium species, even Bacille CalmetteGuerin, enabling the use of IGRA instead of the tuberculin skin test for patients previously vaccinated with Bacille Calmette-Guerin.…”

Initial results of QuantiFERON-TB Gold testing in patients with uveitis

“…They reported that 31% of patients with TB disease were QFT-G positive and TST negative, whereas none were QFT-G negative and TST positive. 8 In our study, there were four patients on immunosuppressive medications: two tested QFT-G positive, one negative, and one indeterminate. There were no patients with HIV infection or lymphopenic disorders.…”