Table 1.

Laboratory diagnosis among patients clinically diagnosed with hepatitis A, acute hepatitis B, chronic hepatitis B and other acute hepatitis, March 2008–December 2009, Guyuan prefecture sentinel sites, Ningxia autonomous region, China (Bold values denote positive predictive values).^a

Clinical diagnosis	Diagnosis on the basis of laboratory test results					Not tested	Grand total
	Acute Ab	Acute Bc	Chronic Bd	NonA–NonBe	Total tested
Hepatitis A	444 (92%)f	6 (1%)	30 (6%)	4 (1%)	484	40	524
Acute hepatitis B	9 (8%)	35 (33%)g	58 (54%)	5 (5%)	107	14	121
Chronic hepatitis B	13 (1%)	75 (8%)	792 (89%)h	12 (1%)	892	57	949
Un-specified/other acute hepatitis	12 (21%)	2 (4%)	20 (36%)	22 (39%)	56	5	61
Total	478	118	900	43	1539	116	1655

^aExcludes one case with markers of acute hepatitis A and B.

^bPositive for IgM antibodies to hepatitis A virus (HAV).

^cPositive for IgM antibodies to hepatitis B virus core antigen (anti-HBc IgM).

^dPositive for hepatitis B virus surface antigen (HBsAg), with no IgM antibodies against hepatitis viruses.

^eNo serological markers of hepatitis A or B.

^f444 out of 484 cases clinically diagnosed as hepatitis A had laboratory-confirmed hepatitis A (positive predictive value: 92%).

^g35 out 107 cases clinically diagnosed as acute hepatitis B had laboratory-confirmed acute hepatitis B (positive predictive value: 33%).

^h792 out of 892 cases clinically diagnosed as chronic hepatitis B had laboratory-confirmed chronic hepatitis B (positive predictive value: 89%).