Front-Loading Sputum Microscopy Services: An Opportunity to Optimise Smear-Based Case Detection of Tuberculosis in High Prevalence Countries

Table 1

Incremental yield of serial smears collected as spot-morning-spot or spot-Xspot-morning specimens.

Country	𝑁^∗	≥1 pos. smear,	First spot pos.	Standard approach			Front-loaded approach
		N (%)	N (%)	Incremental yield, N (%)		N (%) detected	Incremental yield, N (%)		N (%) detected
				Morning	Second spot		Xspot	Morning
Ethiopia	243	52 (21)	45 (87)	4 (8)	2 (4)	51(98)	4 (8)	3 (6)	52 (100)
Nepal	206	55 (25)	39 (71)	7 (13)	5 (9)	51 (93)	5 (9)	6 (11)	50 (91)
Nigeria	224	48 (21)	45 (94)	3 (6)	0	48 (100)	2 (4)	1 (2)	48 (100)
Yemen	250	61 (24)	52 (85)	8 (13)	0	60 (98)	7 (12)	1 (2)	60 (98)
All	923	216 (23)	181 (84)	22 (10)	7 (3)	210 (97)	18 (8)	11 (5)	210 (97)

^∗𝑁 = number; pos = positive; Xspot = Extra spot collected one hour after the first spot sputum specimen.