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Liver, bone and pancreas enzymes

15 min

Skills you'll build2 skills
  • Tell a hepatocellular from a cholestatic pattern using AST, ALT, ALP, and GGT
  • Judge an amylase or lipase rise against its nonpancreatic causes and time course

Try first

Try first

A 34-year-old man is healing from a femur fracture. His alkaline phosphatase (ALP) is 188 U/L (reference interval 35–104 U/L). Gamma-glutamyl transferase (GGT) is 22 U/L (8–61 U/L), and AST, ALT and bilirubin are within their intervals. Where does the extra ALP most likely come from?

Keep going to see the reasoning.

Right. Keep going to follow the reasoning.

Keep going to see the reasoning.

Keep going to see the reasoning.

Get the idea

Use the explanation to check your first decision.

Liver enzyme patterns

Aspartate aminotransferase (AST), alanine aminotransferase (ALT), ALP and GGT mark injury or cholestasis. Liver function itself is judged from other tests, such as albumin and clotting-factor activity.1 Express each enzyme as a multiple of its upper reference limit, then compare them.

PatternAST and ALTALPGGT
HepatocellularIncreased out of proportion to ALPNormal or mildly increasedVariable
CholestaticNormal or mildly increasedIncreased out of proportion to AST and ALTIncreased
Bone source of ALPWithin intervalIncreasedWithin interval

ALT is the more liver-specific aminotransferase. AST also comes from skeletal muscle, heart and red cells, so hemolysis and muscle injury raise AST more than ALT.1

Source of a raised ALP

Liver and bone supply most serum ALP. Growing bones raise ALP in children and adolescents, and the placenta adds ALP in pregnancy. The reference interval therefore depends on age and sex.2

A raised GGT beside a raised ALP supports a liver or bile duct source. A GGT within its interval points toward bone or another source. Alcohol and enzyme-inducing drugs also raise GGT, so an isolated GGT is a poor screening test.1,3

Amylase and lipase

Acute pancreatitis needs two of three findings: typical pain, amylase or lipase at least 3 times the upper reference limit, and typical imaging. Lipase is preferred because it is more specific for the pancreas and stays increased longer.4

Amylase rises within hours of pancreatic injury and often returns toward baseline in 3 to 5 days. Kidney impairment, salivary gland disease, other abdominal disease and macroamylasemia also raise it. Very high triglycerides can suppress some amylase methods.5 Reduced kidney clearance can raise lipase without pancreatic injury. The height of either enzyme does not measure how severe the pancreatitis is.6

Follow the bench demonstration

Sources for this step
References
  1. Kwo PY, Cohen SM, Lim JK. ACG clinical guideline: evaluation of abnormal liver chemistries. Am J Gastroenterol. 2017;112(1):18-35. doi:10.1038/ajg.2016.517
  2. Mayo Clinic Laboratories. Alkaline phosphatase, total and isoenzymes, serum. Accessed September 27, 2026. https://www.mayocliniclabs.com/test-catalog/Overview/622157
  3. Mayo Clinic Laboratories. Gamma-glutamyltransferase, serum. Accessed September 27, 2026. https://www.mayocliniclabs.com/test-catalog/overview/8677
  4. Tenner S, Vege SS, Sheth SG, et al. American College of Gastroenterology guidelines: management of acute pancreatitis. Am J Gastroenterol. 2024;119(3):419-437. doi:10.14309/ajg.0000000000002645
  5. Mayo Clinic Laboratories. Amylase, total, serum. Accessed September 27, 2026. https://www.mayocliniclabs.com/test-catalog/Overview/8352
  6. Mayo Clinic Laboratories. Lipase, serum. Accessed September 27, 2026. https://www.mayocliniclabs.com/test-catalog/Overview/8328

Watch one

Read each decision and its explanation.

An outpatient's liver panel comes back from the Meniscus CX-800 with QC in control.

Which pattern do these enzymes show, and where does the ALP come from?

TestResultReference intervalFlag
AST64 U/L High8–43 U/L8–43High
ALT71 U/L High7–45 U/L7–45High
ALP612 U/L High35–104 U/L35–104High
GGT488 U/L High8–61 U/L8–61High
Total bilirubin4.2 mg/dL High0.0–1.2 mg/dL0.0–1.2High

Specimen: H 5, L 10, I 4. Serum, clean venipuncture

  1. Check the specimen first. The hemolysis index is 5, so the AST rise is not from hemolysis.

    Broken red cells release AST, so a hemolyzed tube can falsely raise AST.

  2. Scale the aminotransferases: AST 64 ÷ 43 U/L = 1.5 times, ALT 71 ÷ 45 U/L = 1.6 times the upper limit.

    Multiples of the upper limit put enzymes with different intervals on one scale.

  3. Scale the ALP: 612 ÷ 104 U/L = 5.9 times the upper limit, far more than the aminotransferases. The pattern is cholestatic.

    The pattern depends on which enzyme rises out of proportion to the other.

  4. Read the GGT: 488 ÷ 61 U/L = 8.0 times the upper limit, which supports a liver or bile duct source.

    GGT distinguishes a liver source of ALP from a bone source.

  5. Read the bilirubin: 4.2 mg/dL fits the cholestatic pattern.

    Conjugated bilirubin backs up when bile flow is obstructed.

The enzymes show a cholestatic pattern with a hepatobiliary source of ALP. ALP is 5.9 times and GGT 8.0 times the upper limit, with AST and ALT near 1.5 times. The cause is assigned from the rest of the workup.

Practice this skill

Your turn

Problem 1 of 3 · Hints available

Alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) are both increased. What does the GGT result contribute?

Correct. An increased GGT beside an increased ALP supports a hepatobiliary source. Alcohol and enzyme-inducing drugs also raise GGT, which limits its specificity.

Incorrect. Bone disease leaves GGT within its interval, so a raised ALP with a GGT inside its interval suggests a bone source.

Incorrect. A hepatocellular pattern is read from the aminotransferases (AST and ALT) increased out of proportion to ALP. GGT helps identify the source of the ALP.

Hint
  1. Liver and bone supply most serum ALP.
  2. Ask which of the two sources also raises GGT.

Review Alkaline phosphatase, GGT, and 5′-nucleotidase

Problem 2 of 3 · Hints available

A 70-year-old woman with chronic kidney disease has a routine panel. Amylase is 1.8 times and lipase 1.4 times the upper reference limit. Creatinine is 3.1 mg/dL, as it was 3 months ago. She has no abdominal pain. Which interpretation of the enzymes is supported?

Kidney impairment raises amylase and lipase without pancreatic injury. Neither enzyme reaches 3 times the upper limit, and there is no pain.

An enzyme above its interval is not enough. The criterion is at least 3 times the upper limit together with typical pain or imaging, and kidney disease explains these small rises.

Read any amylase increase as pancreatitis

Amylase rises with renal impairment, salivary disease, other abdominal disease, and macroamylasemia, and it returns toward baseline within 3 to 5 days. Reading every increase as pancreatic injury mislabels these causes. Lipase is more specific for the pancreas and stays increased longer.

Macroamylase is suspected when a raised serum amylase persists with a low urine amylase. Lipase is raised too here, and the kidney disease already explains both.

Hint
  1. Check each enzyme against the acute pancreatitis criterion.
  2. Ask how the kidney handles amylase and lipase.

Review Pancreatic enzymes

Problem 3 of 3 · On your own

An inpatient's panel shows AST 690 U/L (8–43 U/L), ALT 910 U/L (7–45 U/L), ALP 150 U/L (35–104 U/L) and GGT 75 U/L (8–61 U/L). The hemolysis index is within limits. Which pattern fits?

ALP is 1.4 times and GGT 1.2 times the upper limit. AST and ALT are 16 and 20 times the upper limit, so the aminotransferases dominate.

GGT is raised beside the ALP, which points to the liver. The large aminotransferase rise also shows liver cell injury.

AST (16 times) and ALT (20 times the upper limit) rise far out of proportion to ALP (1.4 times). A clean specimen and the larger ALT rise point to injured liver cells.

Review Hepatobiliary and bone enzyme patterns

Use it

Read the case evidence, then make each decision. The step is complete without it.

  • Tobias Agar, 44, arrives at the emergency department with severe upper abdominal pain that began 10 hours ago.
  • His serum is milky. The lipemia index is 900.
  • Your procedure's lipemia limit is 500 for amylase and 1,500 for lipase.
TestResultReference intervalFlag
Lipase1,020 U/L High13–60 U/L13–60High
Amylase88 U/L28–100 U/L28–100
Triglycerides2,400 mg/dL High<150 mg/dL<150High
Creatinine0.9 mg/dL0.7–1.3 mg/dL0.7–1.3

Specimen: H 10, L 900, I 2. Serum, drawn in the emergency department

Decision 1 of 3

What does the amylase of 88 U/L show?

The lipemia index is above the amylase limit, and very high triglycerides can suppress some amylase methods. This result cannot be used to exclude pancreatic injury.

Amylase takes 3 to 5 days to fall back toward baseline. The pain began 10 hours ago.

An index of 900 is above the amylase limit of 500. Very high triglycerides can suppress some amylase methods, so this value cannot be relied on.

Review Specimen integrity and interference

Decision 2 of 3

What do you do with the amylase?

The specimen is outside the amylase method's lipemia limit, so the number may be falsely low.

The lipemia comes from his triglycerides of 2,400 mg/dL. A new tube drawn today would be just as milky.

The patient's own lipids cause the lipemia, so the laboratory treats this tube. Ultracentrifugation or the procedure's other clearing step can give a reportable amylase.

The comment would describe a result that is not reliable at this lipemia index.

Review Specimen integrity and interference

Decision 3 of 3

What do you do with the lipase?

Each test has its own limit. Lipase is reportable now, and waiting delays a result that is ready.

The lipemia index of 900 is below the lipase limit of 1,500. At 1,020 U/L, lipase is 17 times the upper limit, well past the 3-times criterion, and its early rise fits pain that began 10 hours ago.

The result is inside the method's range and the specimen is within its limit. A dilution is not needed.

Review Specimen integrity and interference

The lipemia index of 900 was compared with each test's own limit. It is above the amylase limit and below the lipase limit, so the amylase within its interval may be a method effect, and the lipase is reportable.

For reference

Sources checked