Simple measures are as effective as invasive techniques in the diagnosis of pulmonary tuberculosis in Malawi.
METHODS
Detection of smear-positive pulmonary tuberculosis (PTB) cases is vital for tuberculosis (TB) control. Methods to augment sputum collection are available, but their additional benefit is uncertain in resource-limited settings.


OBJECTIVE
To compare the diagnostic yields using five methods to obtain sputum from adults diagnosed with smear-negative PTB in Malawi.


METHODS
Self-expectorated sputum was collected under supervision for microscopy and mycobacterial culture in the study laboratory. Confirmed smear-negative patients provided physiotherapy-assisted sputum and induced sputum, followed the next morning by gastric washing and bronchoalveolar lavage (BAL) samples.


RESULTS
A total of 150 patients diagnosed with smear-negative PTB by the hospital service were screened; 39 (26%) were smear-positive from supervised self-expectorated sputum examined in the study laboratory. The remaining 111 confirmed smear-negative patients were enrolled in the study; 89% were human immunodeficiency virus positive. Seven additional smear-positive cases were diagnosed using the augmented sputum collection techniques. No differences were observed in the numbers of cases detected using the different methods. Of the 46 smear-positive cases, 44 (95.6%) could be detected from self-expectorated and physiotherapy-assisted samples.


CONCLUSIONS
For countries such as Malawi, the best use of limited resources to detect smear-positive PTB cases would be to improve the quality of self-expectorated sputum collection and microscopy. The additional diagnostic yield using BAL after induced sputum is limited.
Bell
D J
DJ
Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Liverpool, UK. belldavidj@gmail.com
Dacombe
R
R
Graham
S M
SM
Hicks
A
A
Cohen
D
D
Chikaonda
T
T
French
N
N
Molyneux
M E
ME
Zijlstra
E E
EE
Squire
S B
SB
Gordon
S B
SB
D000293:Adolescent; D000328:Adult; D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D005260:Female; D006801:Humans; D008295:Malawi; D008297:Male; D008875:Middle Aged; D013048:Specimen Handling / Q000379:methods*; D013183:Sputum / Q000382:microbiology*; D013270:Stomach / Q000382:microbiology; D007507:Therapeutic Irrigation; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D055815:Young Adult