Diagnostic yield of repeated smear microscopy examinations among patients suspected of pulmonary TB in Shandong province of China.
OBJECTIVE
To analyse the yield of five repeated smear microscopy examinations for the diagnosis of smear-positive pulmonary tuberculosis (TB).


METHODS
Patients with respiratory symptoms and abnormal chest X-rays provided five spontaneous sputum samples for acid-fast bacilli (AFB) smear microscopy in one of nine county laboratories.


RESULTS
Of 9302 patients with respiratory symptoms and abnormal X-rays, 6437 (69%) had at least one smear-positive sputum. Of these, 84.5% were diagnosed on the first smear, 96.7% on the first two smears, and 99.9% on the first three sputum smears. The fourth and fifth sputum smears yielded only seven additional cases (0.1%).


CONCLUSIONS
Smear microscopy examination of two spontaneous sputum specimens is the most efficient, and three sputum smear examinations provide a diagnosis in almost all cases.
Wu
Z L
ZL
Shandong Center for Tuberculosis Control, Jinan, China. wuzhilei@sohu.com
Wang
A Q
AQ
D002681:China; D006801:Humans; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*