Duration of cough, TB suspects' characteristics and service factors determine the yield of smear microscopy

L Otero, R Ugaz, G Dieltiens, E Gonzalez, K Verdonck, C Seas, A Van Deun, E Gotuzzo, P Van der Stuyft

    Research output: Contribution to journalA1: Web of Science-articlepeer-review


    Objective To determine the efficiency of routine tuberculosis (TB) case detection by examining sputum smear positivity for acid-fast bacilli in relation to duration of cough, characteristics of TB suspects examined and health service factors. Method We combined patient interviews with routine data from laboratory registers in 6 health care facilities in San Juan de Lurigancho district, Lima, Peru. A TB case was defined as a TB suspect with at least one positive sputum smear. We calculated adjusted odds ratios with 95% confidence intervals for the association between smear positivity and health service and patient's characteristics. Results Smear positivity was 7.3% (321/4376). Of the 4376 adults submitting sputa, 55.3% (2418) reported cough for <14 days. In this group, smear microscopy yielded 3.2% (78/2418) positive results vs. 12.4% (243/1958) in patients coughing for 14 or more days. Having cough for >2 weeks, being referred by health care staff, attending a secondary-level health care facility, male sex and age between 15 and 44 years were independent determinants of smear positivity. Conclusions Routine case detection yields a low proportion of smear-positive cases because of the inclusion of a high proportion of patients without cough or coughing for <2 weeks. Adherence to the national TB control programme guidelines on the selection of TB suspects would have a positive impact on the smear positivity rate, reduce laboratory costs and workload and possibly improve the reading quality of smear microscopy
    Original languageEnglish
    JournalTropical Medicine and International Health
    Issue number12
    Pages (from-to)1475-1480
    Number of pages6
    Publication statusPublished - 2010


    • B780-tropical-medicine
    • Bacterial diseases
    • Tuberculosis
    • Mycobacterium tuberculosis
    • Case detection
    • Efficiency
    • Examination
    • Sputum microscopy
    • Smear-positive
    • Acid-fast bacilli
    • Associations
    • Determinants
    • Duration
    • Cough
    • Signs and symptoms
    • Referral
    • Peru
    • America-Latin


    Dive into the research topics of 'Duration of cough, TB suspects' characteristics and service factors determine the yield of smear microscopy'. Together they form a unique fingerprint.

    Cite this