Diagnostic and economic value of carcinoembryonic antigen, carbohydrate antigen 19-9, and carbohydrate antigen 72-4 in gastrointestinal cancers

Table 11 Economic analysis of carcinoembryonic antigen, carbohydrate antigen 19-9, and carbohydrate antigen 72-4 in several situations for gastrointestinal cancers

	Cut-off value	Proportion of endoscopy	Missed diagnosis rate	Total cost ($)	Cost per capita ($)	Total C/E ($)	C/E per capita ($)	Remarks
Non-blood test	-	1.000	0.000	3574.3	146.9	3574.3	146.9	Gold standard
CEA (μg/L)	0.0	1.000	0.000	3691.9	151.7	3691.9	151.7	Lowest cut-off value
	2.5	0.230	0.451	1718.1	38.7	3130.1	70.6	Highest youden index
	4.3	0.065	0.642	990.0	14.6	2767.1	40.7	Lowest total cost-effectiveness ratio
	5.0	0.049	0.674	903.1	12.1	2770.9	37.1	Traditional diagnostic cut-off value
	8.7	0.020	0.759	783.9	7.8	3246.2	32.2	Lowest total cost & lowest cost-effectiveness ratio per capita
CA19-9 (kU/L)	0.0	1.000	0.000	3755.4	154.3	3755.4	154.3	Lowest cut-off value & lowest total cost-effectiveness ratio
	20.0	0.121	0.665	1836.7	25.3	5485.7	75.5	Highest youden index
	36.9	0.033	0.787	1398.5	12.2	6578.5	57.5	Lowest total cost & lowest cost-effectiveness ratio per capita
	37.0	0.032	0.789	1405.2	12.2	6656.1	57.7	Traditional diagnostic cut-off value
CA72-4 (kU/L)	0.0	1.000	0.000	3755.4	154.3	3755.4	154.3	Lowest cut-off value & lowest total cost-effectiveness ratio
	3.4	0.231	0.623	2670.7	41.4	7083.5	109.7	Highest youden index
	6.0	0.126	0.756	2584.5	25.9	10605.1	106.2	Traditional diagnostic cut-off value
	10.5	0.064	0.833	2451.6	16.8	14709.6	100.7	Lowest total cost & lowest cost-effectiveness ratio per capita
CEA	5.0	0.069	0.601	1365.1	22.4	3419.2	56.1	Traditional diagnostic cut-off value in parallel
CA19-9	37.0
CEA	6.9	0.036	0.676	1309.0	17.4	4034.6	53.8	Lowest cut-off value & lowest total cost-effectiveness ratio in parallel
CA19-9	69.2
CEA	3.9	0.098	0.554	1455.6	26.7	3264.3	59.8	Lowest total cost-effectiveness ratio in parallel
CA19-9	38.1
CEA	5.0	0.012	0.862	2433.3	13.8	17661.0	100.0	Traditional diagnostic cut-off value in serial
CA19-9	37.0
CEA	5.4	0.042	0.689	1437.7	18.4	4621.3	59.1	Lowest cut-off value & lowest total cost-effectiveness ratio in serial
CA19-9	0.0
CEA	2.1	0.335	0.361	2339.4	61.4	3659.5	96.1	Lowest total cost-effectiveness ratio in serial
CA19-9	0.0
CEA	5.0	0.044	0.666	1362.9	18.7	4079.6	56.0	Traditional diagnostic cut-off value in the logistic model
CA19-9	37.0
CEA	4.9	0.052	0.641	1341.0	19.8	3732.7	55.1	Lowest cut-off value & lowest total cost-effectiveness ratio in the logistic model
CA19-9	23.2
CEA	2.0	0.213	0.436	1874.8	43.5	3321.5	77.0	Lowest total cost-effectiveness ratio in the logistic model
CA19-9	33.5

The economic indicators were total cost, cost per capita and their cost-effectiveness ratios. The cut-off value with the lowest total cost equaled that of the lowest cost-effectiveness ratio per capita. In the parallel test, any positive result of carcinoembryonic antigen (CEA) or carbohydrate antigen 19-9 (CA 19-9) was considered positive, while both of the positive results of CEA and CA19-9 were considered positive in the serial test. The logistic model was CEA × 2.02 + CA19-9 × 0.06, which made the area under the curve highest. C/E: Cost-effectiveness ratio; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; CA72-4: Carbohydrate antigen 72-4.