High yield of culture-based diagnosis in a TB-endemic setting
Journal Article
2012
Permanent link to this Item
Authors
Journal Title
BMC Infectious Diseases
Link to Journal
Journal ISSN
Volume Title
Publisher
BioMed Central Ltd
Publisher
University of Cape Town
Faculty
Series
Abstract
BACKGROUND: In most of the world, microbiologic diagnosis of tuberculosis (TB) is limited to microscopy. Recent guidelines recommend culture-based diagnosis where feasible. METHODS: In order to evaluate the relative and absolute incremental diagnostic yield of culture-based diagnosis in a high-incidence community in Cape Town, South Africa, subjects evaluated for suspected TB had their samples processed for microscopy and culture over a 21 month period. RESULTS: For 2537 suspect episodes with 2 smears and 2 cultures done, 20.0% (508) had at least one positive smear and 29.9% (760) had at least one positive culture. One culture yielded 1.8 times more cases as 1 smear (relative yield), or an increase of 12.0% (absolute yield). Based on the latter value, the number of cultures needed to diagnose (NND) one extra case of TB was 8, compared to 19 if second specimens were submitted for microscopy. CONCLUSION: In a high-burden setting, the introduction of culture can markedly increase TB diagnosis over microscopy. The concept of number needed to diagnose can help in comparing incremental yield of diagnosis methods. Although new promising diagnostic molecular methods are being implemented, TB culture is still the gold standard.
Description
Reference:
Demers, A. M., Verver, S., Boulle, A., Warren, R., Van Helden, P., Behr, M. A., & Coetzee, D. (2012). High yield of culture-based diagnosis in a TB-endemic setting. BMC infectious diseases, 12(1), 218.