What is amylase?
Amylase is an enzyme that breaks down starches (polysaccharides) into simple sugars. It is produced by two main sources: the pancreas (pancreatic amylase) and the salivary glands (salivary amylase). In acute pancreatitis, amylase leaks from the damaged pancreas into the blood, rising rapidly within 6-12 hours of an attack and remaining elevated for 3-5 days. However, amylase is not perfectly specific for pancreatitis, so lipase (which stays elevated longer and is more specific) is now preferred at most hospitals.
Amylase normal range
| Category | Normal Range (U/L) |
|---|---|
| Adults | 23 – 85 U/L (varies by lab; some labs up to 160) |
| Amylase in pancreatitis | Typically > 3x upper limit (i.e., > 300 U/L) |
Causes of high amylase
| Cause | Level | Notes |
|---|---|---|
| Acute pancreatitis | Very high (>3x ULN) | Gallstones or alcohol most common causes |
| Chronic pancreatitis | Mildly elevated or normal | May not rise significantly |
| Salivary gland disease (mumps, blocked duct) | Elevated | Salivary isoenzyme elevated, not pancreatic |
| Perforated peptic ulcer | Elevated | Pancreatic leakage from nearby inflammation |
| Intestinal obstruction / ischemia | Elevated | Non-specific |
| Kidney disease | Elevated | Kidneys clear amylase; reduced clearance |
| Macroamylasaemia | Persistently mildly elevated | Amylase bound to protein; harmless but confusing |
| Ectopic pregnancy / ovarian cyst | Elevated | Fallopian tube produces some amylase |
Amylase vs lipase — which is better?
Lipase is now the preferred test for suspected pancreatitis. It is more sensitive and specific than amylase, and stays elevated for longer (up to 14 days vs 3-5 days for amylase). If lipase is available, amylase adds little additional diagnostic information. However, amylase is useful for detecting salivary gland disease (lipase does not rise in salivary conditions) and as a rapid bedside check where lipase is not available.
Questions to ask your doctor
- Should I have lipase tested as well?
- What caused my pancreatitis — gallstones, alcohol, medication?
- Do I need an abdominal ultrasound or CT scan?
- If it is chronic pancreatitis, do I need enzyme replacement supplements?