Prevalence of purified protein derivative positivity in human immunodeficiency virus infected individuals in Hong Kong.

Objective: To study the prevalence of skin positivity to purified protein derivative (PPD) in human immunodeficiency virus (HIV)-infected patients in Hong Kong.
Methods: Consecutive clients of an HIV clinic were administered the PPD test and 2 units of PPD-RT23 were used. The area of induration was then measured in 48 to 72 h. Results were related to patient characteristics and HIV-related parameters.
Results: Eight (17.0%) out of 47 clients tested positive to the administration of 2 units of PPD-RT23. If the cutoff were raised to 10 mm according to current practice, only two (4.3%) would test positive.
Conclusion: The prevalence of PPD positivity in HIV-infected patients in Hong Kong is 17%, when a cutoff of 5 mm is used. This figure may form the basis for further studies on the utility of isoniazid preventive therapy in this group of patients.