Introduction of resistance testing might be an inappropriate use of resources

EDITOR—Lilford et al argue for starting randomised studies of new health technologies as early as possible, even if the technology is in a phase of rapid development.1 Many of the points discussed are highly relevant to assays measuring drug resistance in patients with HIV infection.

These assays are currently primarily used as research tools, but recent articles and clinical guidelines have recommended that they should be routinely performed to guide the selection of antiretroviral drugs in the management of patients with HIV infection.2 The basis for these recommendations is not clear: the arguments are more complex than they first seem, and the empirical evidence that resistance testing improves clinical outcome is limited.3

The most commonly used form of resistance testing entails DNA sequencing of the reverse transcriptase and protease genes. But quality assurance studies have found …