This advice note has been prepared to assist colleagues who are developing a business case for presentation to PCT commissioners for the provision of TB Services in their area. It has been prepared by Professor Peter Ormerod based on his experiences in the North West of England, and will be “a living document”.
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Although NICE recommends IGRA, it is apparent that many PCTs have indicated that they won’t pay for it. It is therefore important that Trusts demonstrate to the PCT(s) that their use is cost-effective. (See Gray M, Ormerod LP. An economic evaluation of the use of interferon gamma release assays in the screening of contacts and new entrants for latent TB. Thorax 2007:Vol 62 Suppl III: S49A pA22 BTS Winter Meeting 2007.)
PCTs can be given 2 options.
a) ALL persons up to age 35 with an inappropriately positive tuberculin test WILL be put on preventive TB treatment as per NICE recommendation, at a median cost per case of £450 (NICE 2006 economic data), OR
b) IGRA testing to be done on those potentially for treatment of LTBI, and only those with a positive IGRA test given treatment (see Gray and Ormerod above).
The author of this advice note was sufficiently confident that if the PCT agreed to option (b), the Trust would report the results after 12 months and change if not cost-effective. These results, reported at the 2007 BTS Winter meeting for this purpose, certainly for QFT showed very substantial cost savings (the year 2 data are even stronger). Essentially the ‘neutral’ cut off point is an 8% false positive tuberculin test rate, if more than 8% have a negative QFT then there is net saving which increases with the proportion of negative IGRA testing. The false positive rate with T-spot would have to be higher to be of economic benefit, because of the higher system cost per item.
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