Spot or early morning sample for mycobacterial culture: which?

Drug resistance studies ideally require two sputum specimens, one spot and one early morning, for culture in Löwenstein-Jensen medium. Although the type of specimen plays a major role in the detection of acid-fast bacilli using microscopy, this type of specimen collection puts unnecessary pressure on patients. Two sputum samples, one on the spot and another in the early morning, collected from 179 TB patients in cetylpyridinium chloride and processed for culture, yielded respectively 89.9% and 87.7% culture positivity, while culture positivity increased to 93.3% when both specimens were tested.