Unit Converter
Lipase
(Pancreatic Enzyme – Key Marker for Acute Pancreatitis & Pancreatic Injury)
Synonyms
- Pancreatic lipase
- Serum lipase
- Triacylglycerol acylhydrolase
- Lipolytic enzyme
Units of Measurement
- nkat/L
- µkat/L
- nmol/(s·L)
- µmol/(s·L)
- U/L
- IU/L
- µmol/(min·L)
- µmol/(h·L)
- µmol/(h·mL)
Unit Relationships
1 katal (kat)
= 1 mol/sec of activity (SI unit)
1 kat = 10⁶ µkat = 10⁹ nkat
1 U (Unit) = 1 µmol/min = 16.67 nmol/sec
1 U/L ≈ 0.0167 µkat/L
1 U/L ≈ 16.7 nkat/L
(Lipase activity is measured in U/L in almost all clinical settings.)
Description
Lipase is a pancreatic enzyme responsible for:
- Hydrolysis of dietary triglycerides → free fatty acids + glycerol
Serum lipase is:
- Produced almost entirely by the pancreas
- More specific for pancreatic injury than amylase
- Elevated primarily in acute pancreatitis
Physiological Role
Lipase plays key roles in digestion:
- Breaks down long-chain triglycerides
- Works synergistically with bile acids
- Secreted from pancreatic acinar cells
Clinical Significance
HIGH Lipase
1. Acute Pancreatitis
Lipase increases:
- 3–6 hours after onset
- Peaks at 24 hours
- Remains elevated 7–14 days (longer than amylase)
- 3× ULN is diagnostic
2. Chronic Pancreatitis
Mild to moderate elevation.
3. Pancreatic Cancer
Persistent elevation with other signs.
4. Cholecystitis / Gallstone Disease
Biliary pancreatitis.
5. Renal Failure
Reduced clearance → mild-to-moderate elevation.
6. Bowel Obstruction or Infarction
7. Alcoholic Pancreatitis
8. Drugs
- GLP-1 agonists / DPP-4 inhibitors
- Diuretics
- Opiates
- Valproate
- Thiazides
- Steroids
9. Trauma
Pancreatic injury.
LOW Lipase
Not usually clinically significant except in:
- Cystic fibrosis
- Chronic pancreatitis with exocrine insufficiency
- Total pancreatectomy
Reference Intervals
(Method-dependent; typical values from Tietz 8E, Mayo & ARUP)
Adults
- 13 – 60 U/L (typical)
Interpretation Thresholds
- >3 × ULN (usually >180 U/L) → diagnostic of pancreatitis
- >600–1000 U/L → severe pancreatitis likely
- Normal lipase does NOT exclude pancreatitis in late presentation or hypertriglyceridemia
Children
- Slightly higher in young infants
- Approaches adult range after 1 year
(Each lab must validate method-specific ranges.)
Diagnostic Uses
1. Acute Pancreatitis
Lipase is the preferred test (more specific & longer elevation than amylase).
2. Chronic Pancreatitis
Elevated during flares.
3. Biliary Pancreatitis
Associated with gallstones, elevated LFTs.
4. Pancreatic Tumors
Persistent elevation.
5. Evaluation of Abdominal Pain
Differentiates pancreatic vs non-pancreatic causes.
6. Drug-Induced Pancreatitis
Elevated lipase is a key biochemical signal.
7. Renal Impairment
Interpreted cautiously (delayed clearance).
Analytical Notes
- Serum or plasma acceptable
- Avoid lipemic samples (interference)
- No fasting required
- Levels remain elevated longer than amylase
- Ensure method-specific reference range reporting
- Macro-lipasemia can cause persistent falsely high lipase
Clinical Pearls
- Lipase is more sensitive and specific than amylase for pancreatitis.
- Normal or mildly elevated lipase may occur early or very late in pancreatitis.
- Hypertriglyceridemia can interfere with lipase activity assays.
- Renal failure causes mild elevation (reduced clearance).
- A lipase >1000 U/L is strongly suggestive of severe or biliary pancreatitis.
Interesting Fact
Lipase remains elevated for up to 2 weeks after pancreatitis onset-helping diagnose late-presenting cases where amylase has normalized.
References
- Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Enzymes
- American College of Gastroenterology (ACG) - Acute Pancreatitis Guidelines
- AGA & ASGE Pancreatitis Guidelines
- Mayo Clinic Laboratories - Lipase
- ARUP Consult - Pancreatitis Testing
- MedlinePlus / NIH - Lipase Test