Rapid antigen testing decision tree


1		Base case values	INPUT PARAMETERS	Input values	Outcomes and costs per 10,000 close contacts						Pathway probability	Early isolation	No isolation	Late isolation	Pathway Cost

2		0.1	Covid-19 cases	0.1		Gov-funded RATs	RATs not gov-funded	Difference
3		0.75	Develop symptoms	0.75	Covid-19 cases	1000	1000	0
4			Use RAT \| No Covid-like symptoms		No isolation	184	318	-134
5		1	Government-funded RATs	1	Late isolation	236	566	-330
6		0.2	RATs not government-funded	0.2	Early isolation	580	116	464
7			Use RAT \| Covid-like symptoms		Cost	$111,655	$59,670	$51,985
8		0.7	Government-funded RATs	0.7			Incremental cost per additional early isolated Covid case	$112
9		0.3	RATs not government-funded	0.3
10			Use PCR \| Covid-like symptoms
11		0.2	Government-funded RATs	0.2
12		0.6	RATs not government-funded	0.6
13		0.5	Isolate \| Covid symptoms & not tested	0.5
14			Test characteristics
15		0.58	RAT True +ive (sens) \| no symptoms	0.58
16		0.72	RAT True +ive (sens) \| symptoms	0.72
17		0.98	PCR True +ive (sens)	0.98
18			Resource use and costs
19		$10	RAT cost to the government	$10
20		$150	PCR test cost to the government	$150
21		1	# RATs per day	1
22
23
24
25
26					True +ive					Early isolation	0.058	1	0	0	$10
27				Use RAT	0.58
28				1			No Covid-like symptoms			No isolation	0.011	0	1	0	$10
29			Covid w/ no Covid-like symptoms	$10			0.25
30			0.1		False -ive				True +ive	Late isolation	0.016	0	0	1	$20
31					0.42	No early isolation		Use RAT	0.72
32				Do not use RAT		0.42		0.7	False -ive	No isolation	0.006	0	1	0	$20
33				0				$10	0.28
34									True +ive	Late isolation	0.006	0	0	1	$160
35							Covid-like symptoms	PCR tested	0.98
36		Gov-funded RATs					0.75	0.2	False -ive	No isolation	0.000	0	1	0	$160
37								$150	0.02
38										Late isolation	0.002	0	0	1	$10
39								No testing		0.5
40								0.1		No isolation	0.002	0	1	0	$10
41										0.5
42				Use RAT						No Covid	0.900	0	0	0	$10
43			No Covid	1
44			0.9	$10
45	Covid-19 concerned cohort			Do not use RAT						No Covid	0.000	0	0	0	$0
46				0							1.000
47					True +ive					Early isolation	0.012	1	0	0	$0
48	10000			Use RAT	0.58
49				0.2			No Covid-like symptoms			No isolation	0.022	0	1	0	$0
50			Covid w/ no Covid-like symptoms	$0			0.25
51			0.1		False -ive				True +ive	Late isolation	0.014	0	0	1	$0
52					0.42	No early isolation		Use RAT	0.72
53				Do not use RAT		0.884		0.3	False -ive	No isolation	0.006	0	1	0	$0
54				0.8				$0	0.28
55									True +ive	Late isolation	0.039	0	0	1	$150
56							Covid-like symptoms	PCR tested	0.98
57		RATs not gov-funded					0.75	0.6	False -ive	No isolation	0.001	0	1	0	$150
58								$150	0.02
59										Late isolation	0.003	0	0	1	$0
60								No testing		0.5
61								0.1		No isolation	0.003	0	1	0	$0
62										0.5
63				Use RAT						No Covid	0.180	0	0	0	$0
64			No Covid	0.2
65			0.9	$0
66				Do not use RAT						No Covid	0.720	0	0	0	$0
67				0.8							1.000
68