28.7 Clinical Significance...............................
Normal amylase activity ranges from 80 to 180 SU/dl in serum and from 1500 to
1800 SU/24 h urine specimens. In acute pancreatitis, enzymes from damaged cells
may pass into the blood in considerable amount and more amount of amylase
excreted through urine. In renal failure, the clearance of amylase is reduced and
serum amylase increased, while urinary amylase excretion is normal.
In acute pancreatitis, the serum amylase value reaches from 1000 to 6000 SU/dl at
24 – 48 h after onset of the attack with a concomitant large increase in urinary
amylase. The increase in activity starts within an hour of onset of pain and usually
returns to normal in 4–8 days being partly removed by renal excretion. In chronic
pancreatitis and later stage of carcinoma of pancreas, increased levels of serum and
urinary amylase are observed. Increase of amylase over 1000 SU/dl occurs in biliary
tract disease without pancreatitis. Increase in amylase activity also occurs in intesti-
nal obstruction and perforated peptic ulcer.
28.7 Clinical Significance 115