Study results confirm maintained performance of T-SPOT.TB in repeat testing environment

Oxford Immunotec Ltd, the T cell measurement company, has today announced the outcome of a recent study, which confirmed that the Company’s T-SPOTTM.TB test is more suitable for repeated testing for tuberculosis than the traditionally used Tuberculin Skin Test (‘TST’). The study, which was completed by Luca Richeldi at Modena University Hospital, Italy, addressed one of the main shortcomings with the TST, that the boosting effect of repeat testing induces false positive results in uninfected people. This shortcoming has significant implications for the use of the TST in routine screening programs, including those for healthcare workers.

In the study a group of 44 BCG unvaccinated people who had prior contact with a patient with confirmed multi-drug resistant TB were followed for a period of 2 years and tested with both the TST and T-SPOT.TB after 9, 15 and 24 months. At each time point all 44 individuals remained negative when tested with T-SPOT.TB whilst 3 of them had become TST positive. The results therefore showed that repeated testing did not result in the development of false positive results when using T-SPOT.TB.

Commenting on the reported findings, Peter Wrighton-Smith, Chief Executive Officer of Oxford Immunotec said “This study clearly demonstrates that T-SPOT.TB is unaffected by prior TST testing, even in those individuals who show signs of TST boosting. It is clear that T-SPOT.TB offers a much more reliable tool in screening programs for healthcare workers and in other routine settings than the TST”.