Amylase (Urine)
Sample: 24 hrs urine (Refrigerate. See instructions here)
Schedule: Daily
Units: U/L
Range: Urine 24 hrs 6.5 - 48 U/h Morning sample : Less than 1000 IU/L Amylase/Creatinine clearance ratio: 0.5 - 3.7%
Remarks: 95% of patients with acute pancreatitis have a marked rise in serum amylase within 2-12 hours of onset. The highest serum activity is present 12-72 hours after the onset and usually returns to normal levels in 4-8 days.
Acute non- pancreatic conditions, which may also elevate amylase levels, include acute parotitis, peritonitis, small intestine obstruction, perforated peptic ulcer, rupture of a tubal pregnancy, contraction of the sphincter of Oddi following morphine administration, and mesenteric thrombosis. The Amylase/Creatinine clearance ratio is useful in diagnosis of acute pancreatitis, tubular reabsorption of amylase in the kidney is reduced.
The amylase/creatinine clearance ratio can be assessed with a random urine sample and a simulataneously collected serum sample. In acute pancreatitis, values exceeding 8% are not uncommon. In macroamylasemia, the amylase/creatinine clearance ratio is usually less than 2%.
