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

Table 1 The six schemes and examination prices in economic analysis

Item	Description
Schemes	Scheme 1 Gastrointestinal endoscopy for all people without blood tests
	Scheme 2 Both of gastroscopy and colonoscopy when blood tests were positive
	Scheme 3 Gastroscopy first when blood tests were positive, and then colonoscopy when the result of gastroscopy was negative
	Scheme 4 Colonoscopy first when blood tests were positive, and then gastroscopy when the result of colonoscopy was negative
	Scheme 5 Only gastroscopy when blood tests were positive
	Scheme 6 Only colonoscopy when blood tests were positive
Examination prices	CEA, $4.64; CA19-9, $7.25; CA72-4, $7.25
	Gastroscopy & biopsy, $87.99
	Colonoscopy, $57.98; biopsy after colonoscopy, $32.62

The prices of gastroscopy and colonoscopy did not include that of intravenous anesthesia. The costs of all examinations were from Zhongshan Hospital in 2019. All costs were converted to United States dollars. CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; CA72-4: Carbohydrate antigen 72-4.