Trial-of-antibiotic algorithm for the diagnosis of tuberculosis in a district hospital in a developing country with high HIV prevalence.
OBJECTIVE
To evaluate a diagnostic algorithm for pulmonary tuberculosis based on smear microscopy and objective response to trial of antibiotics.


METHODS
Adult medical wards, Hlabisa Hospital, South Africa, 1996-1997.


METHODS
Adults with chronic chest symptoms and abnormal chest X-ray had sputum examined for Ziehl-Neelsen stained acid-fast bacilli by light microscopy. Those with negative smears were treated with amoxycillin for 5 days and assessed. Those who had not improved were treated with erythromycin for 5 days and reassessed. Response was compared with mycobacterial culture.


RESULTS
Of 280 suspects who completed the diagnostic pathway, 160 (57%) had a positive smear, 46 (17%) responded to amoxycillin, 34 (12%) responded to erythromycin and 40 (14%) were treated as smear-negative tuberculosis. The sensitivity (89%) and specificity (84%) of the full algorithm for culture-positive tuberculosis were high. However, 11 patients (positive predictive value [PPV] 95%) were incorrectly diagnosed with tuberculosis, and 24 cases of tuberculosis (negative predictive value [NPV] 70%) were not identified. NPV improved to 75% when anaemia was included as a predictor. Algorithm performance was independent of human immunodeficiency virus status.


CONCLUSIONS
Sputum smear microscopy plus trial of antibiotic algorithm among a selected group of tuberculosis suspects may increase diagnostic accuracy in district hospitals in developing countries.
Wilkinson
D
D
Centre for Epidemiological Research in Southern Africa, Medical Research Council, Hlabisa, South Africa. david.wilkinson@unisa.edu.au
Newman
W
W
Reid
A
A
Squire
S B
SB
Sturm
A W
AW
Gilks
C F
CF
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis / Q000188:drug therapy; D000328:Adult; D000465:Algorithms; D000658:Amoxicillin / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D004917:Erythromycin / Q000627:therapeutic use*; D005260:Female; D006767:Hospitals, District; D006801:Humans; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000627:therapeutic use*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013019:South Africa; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy
D000900:Anti-Bacterial Agents; D010406:Penicillins; D004917:Erythromycin; D000658:Amoxicillin