Intrinsic and extrinsic factors associated with sputum characteristics of presumed tuberculosis patients

PLoS One. 2019 Dec 27;14(12):e0227107. doi: 10.1371/journal.pone.0227107. eCollection 2019.

Abstract

Background: Sputum remains the most preferred specimen for detection of Mycobacterium tuberculosis due to its non-invasive method of production. Good quality sputum specimen is essential for accurate diagnosis of pulmonary tuberculosis (PTB). It is therefore imperative to assess factors that are related to the production of sputum that is of the best quality.

Objective: We assessed the intrinsic and extrinsic characteristics of presumed tuberculosis patients and the quality of sputum they produced.

Methods: This was a cross-sectional study in which consenting enrolled presumed tuberculosis patients were subjected to medical examination and a structured questionnaire administered to collect clinical history, demographic information, environmental and behavioral characteristics. The enrolled participants were instructed on how to collect spot and morning sputum specimens for macroscopic and microscopic assessment to determine any association.

Results: A total of 309 patients were enrolled into the study with an even distribution on gender (50.5% males). Of these, 202 (65.3%) submitted both a spot and a morning specimen for analysis. On macroscopic examination, 70% spot and 68% morning sputum were characterized as good quality (Purulent/mucoid). The factors associated (p<0.05) with quality specimen included both intrinsic and extrinsic factors. The intrinsic factors included: difficulty in breathing, presence of conjunctivitis and knowledge of the disease whereas the only extrinsic factor associated with production of good quality sputum for tuberculosis diagnosis was time taken by patient to seek tuberculosis treatment after occurrence of any of the TB symptoms.

Conclusion: Both intrinsic and extrinsic factors affected the quality of sputum produced by presumed tuberculosis patients. Clinical and behavioral characteristics including conjunctivitis, difficulty in breathing and delay in seeking treatment were important factors that determined the production of good quality sputum specimens, while knowledge of tuberculosis disease did not compel presumed tuberculosis patients to produce good quality sputum for diagnosis of the disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / isolation & purification*
  • Sputum / microbiology*
  • Tuberculosis / diagnosis*
  • Tuberculosis, Pulmonary / diagnosis*
  • Young Adult

Grants and funding

This work was supported by the Kenya Medical Research Institute, Internal Research Grant L308 to FO (www.kemri.org). Total funding received was $8000. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.