Prolonged, isolated AST elevation is likely benign

A retrospective review from Israel based on analysis of the medical charts of 32 healthy children diagnosed with prolonged, isolated aspartate aminotransferase (AST) elevation at a mean age of 39 months found that none developed significant liver disease. This was true even though at follow-up (at a mean of 65.6 months), AST generally remained elevated—from 1.23 to 12 times the up- per limit of normal—with the abnormality resolving in only 10 patients.

Levels of macro-AST (m-AST) were relatively prevalent; 22% of the children were m-AST positive, and 44% had borderline levels. However, AST levels were no higher in those who were m-AST positive than in those characterized as borderline or negative for m-AST. Investigators did find that the age at presentation was significantly different in those with borderline m-AST levels and those with m-AST–positive levels: 31 months versus 69 months, respectively.

Given these findings, investigators determined that in a healthy child with prolonged, isolated AST elevation and normal lactate dehydrogenase, alanine transaminase, and creatine kinase, further laboratory and imaging investigation usually is unnecessary.

Thoughts from Dr. Farber

We have all often seen this in healthy children and should learn to ignore it, unless clinical findings suggest liver disease or the child is on medicine that is potentially toxic to the liver. Nonetheless, unlike the authors, I would probably still feel compelled to repeat testing in a child with a level 12 times above normal.

Reference

1. Magen-Rimon R, Tal G, Kaplan M, Shaoul R. The significance of isolated aspartate aminotransferase elevation in healthy paediatric patients. Acta Paediatr. Published online September 26, 2021. doi:10.1111/apa.16123