What is the reference range for serum amylase?

• A. 25-130 U/L
• B. 0-50 U/L
• C. 100-300 U/L
• D. 500-1000 U/L

Answer: (A)

Normal serum amylase activity in a healthy adult is about 25 to 130 U/L. This range reflects the typical baseline produced mainly by the pancreas and salivary glands and is what most laboratories consider the upper and lower limits of normal with their standard assay. Values within this interval are not suggestive of acute pathology, while elevations beyond the upper limit can indicate conditions such as pancreatitis or other sources of amylase elevation, though clinical correlation is always needed. The other suggested ranges are not consistent with standard normal intervals—one is too low for normal adults, another is higher than usual upper limits, and the last would represent a clearly abnormal, markedly elevated level.