What Does It Mean if My ALT Is Higher Than AST
ALT higher than AST usually means an ALT-predominant, liver cell stress pattern that is common in fatty liver, viral hepatitis, and drug injury. It is not a diagnosis.
If your ALT is higher than AST, you have an ALT-predominant pattern. This is a hepatocellular pattern, meaning the liver cell itself is the main source of the enzyme rise. It usually points toward liver cell stress from fat, a virus, or a drug, and it is not a diagnosis by itself.
What does it mean if my ALT is higher than AST?
ALT and AST are enzymes that leak from cells. ALT is concentrated in liver cell cytoplasm. AST sits in liver mitochondria but also in skeletal muscle, heart, and red blood cells, so an ALT higher than AST is more specific for liver cell stress. The De Ritis ratio is AST divided by ALT. When ALT is higher, the ratio is below 1.0. That is the formal way of saying the ALT is leading.
A De Ritis ratio below 1.0 is a pattern, not a liver diagnosis. It says which enzyme is leading; it does not say why.
The ratio is named after Fernando De Ritis. A 2013 review in Clinical Biochemist Reviews summarised why clinicians still use it.
The mechanism: why ALT can be higher than AST
One reason is location. ALT sits mainly in hepatocyte cytoplasm, so mild cell stress releases it early. AST has both cytoplasmic and mitochondrial forms and is not liver-only. Another reason is clearance. ALT has a longer half-life than AST, roughly 47 hours versus 17 hours, so after an acute injury ALT stays raised longer and the AST/ALT ratio tends to fall over time as AST clears faster.
| Pattern | AST vs ALT | Common clinical contexts |
|---|---|---|
| ALT higher than AST | De Ritis ratio below 1.0 | Early NAFLD/MASLD, viral hepatitis, drug-related hepatocellular injury |
| AST higher than ALT | De Ritis ratio above 1.0 | Alcohol-related liver injury, muscle release, cirrhosis |
Scroll the table sideways for the rest →
Typical patterns on a lab report, not diagnostic categories.
When an ALT-predominant result is common
- Non-alcoholic fatty liver disease, now often called MASLD. Early disease usually shows ALT higher than AST, with ALT often one to two times the upper limit. AST can be normal or mildly elevated.
- Viral hepatitis. In acute hepatitis A, B or C both can rise sharply, but ALT commonly leads and stays high longer after the peak.
- Drug or supplement reactions. The hepatocellular type of liver injury usually shows ALT higher than AST.
- Post-exercise. Hard training can push AST up from muscle, but an ALT-predominant pattern is less likely to be explained by muscle alone.
On a lab report this may look like ALT 72 U/L and AST 45 U/L, with a De Ritis ratio of 0.63. That is a classic ALT-predominant result. The actual upper limit matters, because labs use different cut-offs for age and sex.
When the simple answer does not hold
The common mistake is reading the ratio when both enzymes are inside the normal range. If AST is 22 U/L and ALT is 26 U/L, the ratio is 0.85, but that is normal noise. Small differences at low levels do not mean anything.
Alcohol often flips the pattern. Alcohol-related liver injury more often shows AST higher than ALT. An AST:ALT ratio above 2.0 can suggest alcohol when the enzymes are elevated, but this is not a rule. Alcohol can release mitochondrial AST and affect ALT production.
Cirrhosis can invert an ALT-predominant pattern. As fibrosis progresses in NAFLD or viral hepatitis, the ratio may rise above 1.0. Muscle injury, haemolysis, or a macro-AST can raise AST independently.
What to check next: retest, full panel, and when to see a doctor
One ALT/AST pair is not enough. Get a full liver panel: bilirubin, ALP, GGT, albumin, platelets, and if you are checking fibrosis risk, the FIB-4 score. Both ALT and AST have meaningful within-person variation (EFLM biological variation database), so a single ratio can shift without a real change in liver health. A repeat liver panel after 2 to 4 weeks is common if a mild rise has no obvious cause.
Worth asking a doctor about if:
- ALT or AST stays above 2 times the upper reference limit on repeat
- The elevation lasts more than 6 months
- Bilirubin, ALP, albumin or platelets are out of range
- You have jaundice, right upper abdominal pain, new swelling, or unexplained weight loss
A mildly elevated ALT with everything else normal is different from ALT 120 with low platelets.
Put your own numbers into the free De Ritis ratio calculator to see the ratio and its band. If you have a full report, the same free HealthOS blood tool explains every marker and works out the De Ritis ratio for you. A second upload shows how each marker moved, which a one-off ratio cannot show.
Written by
HealthOS Research