Extrapulmonary tuberculosis: a potential source of laboratory-acquired infection.

A three-year retrospective study has demonstrated the effect of extrapulmonary tuberculosis on safety within a routine bacteriology laboratory. The investigation showed that, from 112 patients, 162 specimens considered to present a risk to laboratory staff were processed outside of the B1 protective area. However, it was estimated that only 51 of those specimens were heavily positive. Of these 57% were sputum 30% pus, and 10% urine. Specimens of pus and urine account for 50% of specimens received for non-tuberculosis investigations, and it would be impossible to process all specimens that might present a risk in B1 accommodation and still maintain a high degree of safety. It is recommended that request forms which accompany specimens should clearly indicate potential high-risk specimens.