Raised ALT in dogs: hepatocellular versus cholestatic pattern
5-year-old crossbreed dog with vomiting and lethargy for 3 days. No medication. Not icteric. Biochemistry:
| Parameter | Result | Reference |
|---|---|---|
| ALT | 1,250 U/L | 10–100 |
| AST | 310 U/L | 15–50 |
| Alkaline phosphatase (ALP) | 280 U/L | 20–150 |
| GGT | 8 U/L | 0–10 |
| Total bilirubin | 0.3 mg/dL | 0.0–0.4 |
Which statement about this profile is correct?
chevron_right Show answer and explanation
A. Such a high ALT indicates severely impaired liver function
ALT is a leakage enzyme: it reflects hepatocyte membrane damage, not the functional capacity of the liver. To assess function, look at albumin, urea, glucose, cholesterol, coagulation, bilirubin or bile acids.
B. AST is more liver-specific than ALT and confirms a hepatic origin
It is the other way round: in dogs ALT is fairly liver-specific, whereas AST also comes from muscle and red cells. With a high AST, measure CK.
C. It is a predominantly hepatocellular pattern; ALT indicates injury, but its magnitude does not predict outcome
Correct. The ALT increase (more than 10-fold) far exceeds the ALP increase (under 2-fold) and GGT is normal: hepatocellular injury predominates. The magnitude reflects how many cells are damaged at that moment, not reversibility or residual function.
D. It is a cholestatic pattern because ALP is above the range
A cholestatic pattern shows ALP and GGT increases proportionally greater than ALT, often with hyperbilirubinaemia. Here ALP is only mildly raised (it can rise secondarily to inflammation) and GGT is normal.
lightbulb Key takeaway
ALT and AST are leakage enzymes (hepatocellular injury); ALP and GGT are induced enzymes (cholestasis, drugs). Compare how many times each exceeds its upper limit to define the pattern, and assess liver function with other parameters.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.