A prevalence survey for smear-positive tuberculosis in Thai prisons.

Twenty-seven prisons in Thailand were used for the setting of the study. The objectives were to measure the prevalence of smearpositive tuberculosis (TB) and to compare its detection using the World Health Organization (WHO) guidelines for prisons or the International Standards for Tuberculosis Care (ISTC) criteria. Prisoners who were not on TB medications and who had not been treated for TB in the previous 6 months were enrolled in the survey. Prison nurses conducted a one-time mass screening using the WHO questionnaire with follow-up sputum collection in TB suspects. Of 71 594 prisoners 22 132 (30.9%) were identified as TB suspects and 254 were confirmed by sputum smear for a prevalence of 354.8/100 000. Males were most likely to be diagnosed with TB disease (OR 2.6) as were those transferring in from another prison versus new prisoners (OR 3.0). The positive predictive value of the WHO criteria was 1.2% and that of the ISTC standard was 5.9%. TB prevalence in this survey remained high. WHO guidelines recognised as a standard require health workers to question prisoners and measure height and weight. The ISTC standard a single question about cough >/= 2 weeks is simple may be asked by non-health personnel and may be a better alternative. (authors)