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Liver, bone and pancreas enzymes

15 min

  • 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

Read the full reference

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?

The next section explains it.

Right. The next section explains why.

The next section explains it.

The next section explains it.

Get the idea

Compare the aminotransferases with ALP

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 Read 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

Find where the ALP comes from

Liver and bone supply most serum ALP. Growing bones raise ALP in children and adolescents, and the placenta adds ALP in pregnancy. Age and sex therefore choose the interval.2

A raised GGT beside a raised ALP supports a liver or bile duct source. A GGT inside 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

Read amylase and lipase against their other causes

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

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

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?

TestResultPreviousReference intervalFlag
AST64 U/L8–43 U/LHigh
ALT71 U/L7–45 U/LHigh
ALP612 U/L35–104 U/LHigh
GGT488 U/L8–61 U/LHigh
Total bilirubin4.2 mg/dL0.0–1.2 mg/dLHigh

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

  1. Check the specimen first. The hemolysis index is 5, so the AST comes from the patient.

    Broken red cells release AST, so a hemolyzed tube can fake an AST rise.

  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 is set by 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 tells 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.

A cholestatic pattern with a hepatobiliary source of ALP: ALP 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.

Your turn

Problem 1 of 3

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 is the pattern that points toward bone.

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

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 reading 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

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

  • Tobias Grell, 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.
TestResultPreviousReference intervalFlag
Lipase1,020 U/L13–60 U/LHigh
Amylase88 U/L28–100 U/L
Triglycerides2,400 mg/dL<150 mg/dLHigh
Creatinine0.9 mg/dL0.7–1.3 mg/dL

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 tell you?

The lipemia index is above the amylase limit, and very high triglycerides can suppress some amylase methods. This number cannot argue against 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 Pancreatic enzymes

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 works on this tube. Ultracentrifugation or the procedure's other clearing step can give a reportable amylase.

The comment would describe a number the method cannot vouch for at this lipemia index.

Review Pancreatic enzymes

Decision 3 of 3

What do you do with the lipase?

Each test follows 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 adds nothing.

Review Pancreatic enzymes

The clue that settled this case is the lipemia index read against each test's own limit. At 900 it is above the amylase limit and below the lipase limit. The amylase within its interval is a possible method effect, and the lipase is a reportable result.

Keep

Sources checked