Oxford, UK ; May 26, 2010
The authors of a peer-reviewed article published in the journal “BMC Pulmonary Medicine” concluded that TB contact tracing strategies based on use of the T-SPOT.TB assay are the most cost effective.
Researchers constructed a model to assess the cost, effectiveness and cost effectiveness of five different strategies for screening a cohort of 1000 close contacts of infectious TB. The authors examined costs based on testing with the tuberculin skin test (TST) alone, TST in combination with either the T-SPOT.TB assay or an ELISA-based test (both interferon gamma release assays, or IGRAs), and use of each of these IGRAs alone.
Pooran et al concluded “….using the IGRA, whether in a single or dual strategy, is always cheaper than using only the TST. This finding is very insensitive to changes in variables within reasonable parameters. These data should be considered when selecting a suitable strategy for screening LTBI.”
The model was based on UK pricing for TB diagnosis and treatment, and, unlike some previous analyses, took account of costs associated with potential isoniazid-induced hepatitis.
Cost effectiveness was measured as the additional costs of the respective screening strategies, over the costs of not screening, per active TB case prevented. The T-SPOT.TB assay in combination with TST was calculated to be the most cost-effective approach, with the ELISA-based assay in combination with TST the second most cost-effective approach. IGRA-alone strategies were preferable to the TST alone, with the T-SPOT.TB test being more cost effective than the ELISA-based IGRA within the single test approach.
If total costs per active TB case prevented (rather than additional cost) are calculated for each considered contact tracing strategy, then T-SPOT.TB test alone is the most cost effective approach.
