Table 2– Average unit cost per acid-fast bacilli (AFB) smear on sputum sample/slide for light-emitting diode (LED) with auramine O versus Ziehl–Neelsen (ZN) light microscopy

Type of microscopy	Cost per AFB smear US$
Type of microscopy	Overhead^#	Building space^¶	Equipment⁺	Staff^§	Reagents and chemicals^ƒ	Consumables^##	Total
LED	0.81	0.01	0.08	0.47	0.04	0.22	1.63
ZN	1.06	0.01	0.08	0.69	0.04	0.22	2.10

^#: maintenance, running, management and supervision costs; ^¶: cost relating to the use of specific physical (laboratory space) for procedures relevant for microscopy; ⁺: costs based on annualised cost of laboratory equipment, inclusive of procurement costs; ^§: complete staff hands-on time from the receipt of specimen to dispatch and filing of the result forms; ^ƒ: based on costs of ready-made staining reagents procured by National Health Laboratory Services and ∼3 mL of use per slide for each staining reagent; ^##: cost associated with the use of general consumables such as sputum collection cups, gloves, glass slides, etc.