Diagnosing HIV-associated tuberculosis: reducing costs and diagnostic delay.

Abstract

University-affiliated hospital in South Africa. To assess the time to diagnosis and the yield and laboratory cost of diagnostic procedures in human immunodeficiency virus (HIV) associated tuberculosis. Cohort study. Adult HIV-infected patients with newly-diagnosed tuberculosis admitted over a 2-year period. A total of 141 admissions fulfilled the case definition. Sputum smear yield (43% overall) correlated strongly with chest radiograph appearance but not with CD4+ lymphocyte count. Sputum smear yield was approximately 40% per sample sent, resulting in a high cumulative yield when > or = three samples were sent. Smear of sputum or wide needle lymph node aspirates were the most cost-effective diagnostic methods. Significant diagnostic delay occurred in sputum smear-negative patients. Most patients with sputum smear-negative tuberculosis had either pleural effusions or lymphadenopathy. Lymph node biopsy had a high diagnostic yield even in patients with symmetrical nodes, but was under-utilised in this group. There was unnecessary expenditure on cultures, with many patients having several positive cultures. Repeated sputum smear examination produces a high cumulative yield in HIV-associated tuberculosis. Considerable savings in laboratory utilisation and bed occupancy would have been made if a streamlined diagnostic approach with greater use of lymph node aspirate and early pleural or lymph node biopsy had been followed.