High yield of culture-based diagnosis in a TB-endemic setting

BMC Infectious Diseases

Table 5 Yields and NND calculated on some other recent studies that have used culture based diagnosis in TB suspects

	Our study	Our study SN SE	Monkongdee et al.[32]	Boehme et al.[36]	Ssengooba et al.[35]
Population	HIV pos and neg	SN in HIV pos and neg	All HIV pos	HIV pos and neg	All HIV pos and SN
Pos on 1st S	377		36	561
Pos on 2S	508		45
Pos on 1st C	682	253	97	732	52
Pos on 2C	760	326	113		60
TB suspects tested	2537	2060	1060	1462	170
% Pos on 1st S	0.149		0.034	0.384
% Pos on 2S	0.200		0.042
% Pos on 1st C	0.269	0.123	0.092	0.501	0.306
% Pos on 2C	0.299	0.158	0.107		0.353
RY 2S vs 1S	1.3		1.3
RY 1C vs 1S	1.8		2.7	1.3
RY 1C vs 2S	1.3		2.2
RY 2C vs 1C	1.1	1.3	1.2		1.2
AY 2S vs 1S	0.052		0.008
AY 1C vs 1S	0.120		0.058	0.117
AY 1C vs 2S	0.069		0.049
AY 2C vs 1C	0.031	0.035	0.015		0.047
NND 2S vs 1S	19		118
NND 1C vs 1S	8		17	9
NND 1C vs 2S	15		20
NND 2C vs 1C	33	28	66		21
NND of 1st S	7		29	3
NND of 1st C	4	8	11	2	3

Legend: S = smear, C = culture, Pos = positive, Neg = negative, RY = Relative yield, AY = Absolute yield, SE= suspect episode, NND = number needed to diagnose. In the study by Monkongdee et al. [32], yields were reported using all culture positive cases as the denominator. The results shown here use all suspects tested as the denominator.

ISSN: 1471-2334