@article {Bonnet:September 2007:1027-3719:953,
	author = "Bonnet, M.",
	author = "Ramsay, A.",
	author = "Gagnidze, L.",
	author = "Githui, W.",
	author = "Guerin, P.J.",
	author = "Varaine, F.",
	title = "Reducing the number of sputum samples examined and thresholds for positivity: an opportunity to optimise smear microscopy",
	journal = "The International Journal of Tuberculosis and Lung Disease",
	volume = "11",
	year = "September 2007",
	abstract = "SETTING: Urban health clinic, Nairobi.<P></P>OBJECTIVE: To evaluate the impact on tuberculosis (TB) case detection and laboratory workload of reducing the number of sputum smears examined and thresholds for diagnosing positive smears and positive cases.<P></P>DESIGN: In this prospective study, three Ziehl-Neelsen stained sputum smears from consecutive pulmonary TB suspects were examined blind. The standard approach (A), &#8805;2 positive smears out of 3, using a cut-off of 10 acid-fast bacilli (AFB)/100 high-power fields (HPF), was compared with approaches B, &#8805;2 positive smears (&#8805;4 AFB/100 HPF) out of 3, one of which is &#8805;10 AFB/100 HPF; C, &#8805;2 positive smears (&#8805;4 AFB/100 HPF) out of 3; D, &#8805;1 positive smear (&#8805;10 AFB/100 HPF) out of 2; and E, &#8805;1 positive smear (&#8805;4 AFB/100 HPF) out of 2. The microscopy gold standard was detection of at least one positive smear (&#8805;4 AFB/100 HPF) out of 3.<P></P>RESULTS: Among 644 TB suspects, the alternative approaches detected from 114 (17.7%) (approach B) to 123 cases (19.1%) (approach E) compared to 105 cases (16.3%) for approach A (P &#60; 0.005). Sensitivity ranged between 82.0% (105/128) for A and 96.1% (123/128) for E. The single positive smear approaches reduced the number of smears by 36% compared to approach A.<P></P>CONCLUSION: Reducing the number of specimens and the positivity threshold to define a positive case increased the sensitivity of microscopy and reduced laboratory workload.",
	pages = "953-958(6)",
	url = "http://www.ingentaconnect.com/content/iuatld/ijtld/2007/00000011/00000009/art00005"
}