Serum β-N-acetyl hexosaminidase (β-NAH) as a discriminant between malignant and benign extrahepatic biliary obstruction: Comparison with carcinoembryonic antigen (CEA)

Fifty-one patients (16 with malignant extrahepatic biliary obstruction, ten with benign extrahepatic biliary obstruction, eight with alcoholic liver disease, five with viral hepatitis and 12 with liver metastases) and 19 adult healthy controls were studied with determinations of β-N-acetyl hexosaminidase (a lysosomal enzyme which is cleared from the circulation by the Kupffer cells), carcinoembryonic antigen (CEA), serum bilirubin, alkaline-phosphatase and aspartate aminotransferase (AST). Both CEA and β-NAH were elevated in each disease group. Elevated β-NAH levels distinguished between benign and malignant extrahepatic biliary obstruction better than CEA levels. β-NAH levels for the malignant and the benign groups were 47.6 ± 14.7 U/l and 23.0 ± 4.7 U/l (mean ± S.D.) respectively. The groups differed significantly (P < 0.001). Plasma CEA levels for both groups were 18.7 ± 38.9 and 7.2 ± 3.3 ng/ml (mean ± S.D.) respectively. β-NAH levels for the 19 normal controls were 15.8 ± 3.5 U/l (mean ± S.D.). β-NAH also was significantly elevated in patients with hepatic metastases (36.9 ± 20.1 U/l). In 25 cancer patients with metastases other than in the liver β-NAH levels (18.3 ± 5.2) were not significantly elevated over the control group. It has potential value as a marker for non-CEA-producing liver metastases.