ABSTRACT
Study of tumour markers to differentiate benign and malignant extra hepatic biliary obstructions showed that levels fo serum beta-N-acetylhexosaminidase and lipid associated sialic acid were not different in the two groups. The levels of carcinoembryonic antigen (CEA) and total sialic acid (TSA), on the other hand, were significantly higher in patients with the malignant biliary obstruction. At a cut-off value of 6.4 ng/ml (mean + 2SD) CEA had 66.7 per cent true positivity in malignancy 100 per cent true negativity in control and 78 per cent true negativity in the benign group. Similarly, TSA at a cut off value of 60 mg/dl had 61 per cent true positivity in malignancy, 90 per cent true negativity in controls and 70 per cent true negativity in the benign group. These two tumour markers appear to have similar diagnostic potential for malignant extrahepatic biliary obstruction. Surgical management of the malignant obstruction did not result in a decline in the elevated levels of these two markers during the post-surgical period of 7 days.