J F Huggett, M S Taylor, G Kocjan, et al. Development and evaluation of a real-time PCR assay for detection of Pneumocystis jirovecii DNA in bronchoalveolar lavage fluid of HIV-infected patients. Thorax 2008;63:154–9. There is a typographical error in one of the PCR primers, which will result in the assay not working if this is copied. The forward primer that currently reads 5′-AGTCCGTTTAGCACGCTAC-3′ should read 5′-AGTCCGTTTAGCACGCTCAC-3′.