Does an ALT of 44 U/L suggest MASLD, and does an AST of 22 U/L rule it out?

The claim is well supported: ALT 44 U/L is compatible with MASLD but is diagnostically nonspecific, and AST 22 U/L does not exclude MASLD or clinically important fibrosis.

Clinical interpretation

• ALT 44 U/L exceeds AASLD’s sex-specific “true normal” range for men (approximately 29–33 U/L). Even if not flagged by a laboratory’s reference interval, persistent or intermittent values above 30 U/L may indicate chronic hepatocellular injury.
• This mild elevation can occur with MASLD, especially with metabolic risk factors, but does not demonstrate steatosis, steatohepatitis, or fibrosis stage. Alternative explanations—including alcohol exposure, viral hepatitis, medications/drug-induced injury, autoimmune or iron-related disease, and muscle injury—remain relevant.
• AST 22 U/L, although generally normal, cannot be used to rule out MASLD. Liver-society guidance specifically cautions that normal aminotransferases occur in MASLD, MASH, and advanced fibrosis.

Normal enzymes and fibrosis risk

• In a biopsy-based cohort with ALT and AST both below 40 U/L, 35% had steatohepatitis, 19% bridging fibrosis, and 7% cirrhosis.
• Another biopsy series found normal enzymes in 20.8% of affected people, with advanced fibrosis occurring at a similar frequency to that among people with elevated enzymes.
• A systematic review reported normal ALT in about 25% of NAFLD and 19% of NASH cases. In older adults with diabetes, ALT was elevated in only 12.5% of those with NAFLD-related fibrosis.

Clinical implications

• Steatosis requires imaging, biopsy, or a validated noninvasive assessment; ALT and AST alone cannot establish or exclude disease.
• Fibrosis assessment should use FIB-4 and, when appropriate, transient elastography or another validated noninvasive test.

Bottom line

• ALT 44 U/L is a nonspecific but clinically meaningful signal compatible with MASLD; AST 22 U/L offers no reliable exclusion of MASLD, MASH, or advanced fibrosis.