Table 1. Summary of base case input parameters and sensitivity analyses ranges examined for an analysis of a mobile HIV testing unit Cape Town, South Africa.

Variable		Base Case	Range	Ref.
Baseline cohort characteristics
Male subjects (%)		44	30–80	[26]
Age, mean years (SD)		33 (13)	20–44	[26]
Prevalence of undiagnosed HIV (%)		6.6	1–30	[26]
HIV-infected patients CD4 count at diagnosis (mean cells/µL (SD))
Mobile unit testing	Male*	423 (236)		[26]
	Female	516 (272)		[26]
Medical facility-based testing†	Male	291 (203)		[18], [26]
	Female	357 (242)		[18], [26]
HIV screening
Mobile unit testing characteristics (one-time HIV test and POC CD4 count offer)
HIV test acceptance probability (%)	Male*	97	70–99	[26]
	Female	95	70–99	[26]
Initial HIV test (Bioline HIV-1/2 3.0, Standard Diagnostics, South Korea)				[57]
Test sensitivity (%)		100
Test specificity† (%)		99
Confirmatory HIV test (Determine HIV-1/2, Abbott Laboratories, UK)				[57]
Test sensitivity (%)		100
Test specificity† (%)		100
CD4 count POC test (Alere PIMA™ Analyzer, Waltham, MA, USA)
CD4 count acceptance probability (%)		91	70–99	[26]
CD4 >350 cells/µL	Male*	31	20–98
	Female	51	20–98
CD4 201–350 cells/µL		49	20–98
CD4 <200 cells/µL		58	20–98
Medical facility-based program average HIV test frequency				[18] †
HIV positive result		Every 4.0 yrs	1–10 yrs
HIV negative result		Every 5.7 yrs	1–10 yrs
Loss to follow-up and return to care
Probability of loss to follow-up				[58], [59] †
Pre-ART (monthly)		0.0108	0.005–0.02
On ART (monthly)	Adherence >95%	0.0016
	Adherence <50%	0.0108	0.005–0.02
Probability of return to care				Assumption
With acute WHO stage 3–4 disease or TB		0.50
Without WHO stage 3–4 disease or TB after first year lost (monthly)		0.01	0.005–0.02
ART treatment
Initiation at WHO stage 3–4 disease presentation, TB, or CD4 <350/µL				[9], [32]
Monthly CD4 count increase on suppressive ART (cells/µL)				[41]
Initial 8 weeks		67
After 8 weeks		3
HIV screening costs (2012 US$)
Mobile testing intervention (2-year) (×1,000)				[26]
Purchase and modification		152.0
Mobile van resale value		(56.4)
Medical/counselor salaries‡		216.2
Administrative salaries/maintenance§		209.8
Total 2-year mobile unit intervention cost∥		521.6	250–1,000
No. of individuals offered a test over 2-yrs		18,870	9,440–28,310
Per-person mobile unit cost (excluding HIV test costs)		27.60	13.60–54.40
Initial HIV test		1.70	0–8.50
Confirmatory HIV test		2.00
Total per-person mobile unit cost (including HIV test costs)
HIV-negative result		29.30	14.70–44.00
HIV-positive result		31.30	15.70–46.95
POC CD4 count		7.70	0–38.00
Medical facility-based HIV testing programs¶				[45]
HIV-positive result		13.90
HIV-negative result		9.30
Clinical care costs (2012 US$)
Co-trimoxazole prophylaxis cost (monthly)		1.40		[34]
ART regimen cost (monthly)				[33]
First-line		13.30
Second-line		40.30
Laboratory CD4 count test cost		13.90		[35]
HIV RNA cost		69.50		[35]
Inpatient hospital cost, per day		315.10		[35]
Outpatient hospital cost, per visit		32.60		[35]

^*Statistically significant difference between males and females.

^†Parameter derived and/or calculated from reference data.

^‡Comprising of one nurse practitioner ($84,200), one registered nurse ($71,100), three counselors ($47,500), one educator ($1,200) and one nurse practitioner at 20% time ($12,200).

^§Made up of one driver ($27,100), one project manager ($152,300), one data capturer/administrator ($22,000), diesel ($7,500) and general maintenance ($900).

^∥Assumed that van could be resold after 2 years of use.

^¶Costs include initial and confirmatory HIV test, staff salaries, and space in a voluntary counseling and testing site.

SD: standard deviation; POC: point-of-care; ART: antiretroviral therapy; WHO: World Health Organization; TB: tuberculosis.