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Mildly Elevated Liver Transaminase Levels: Causes and Evaluation

Robert C. Langan, MD
Kourtni A. Hines-Smith, MD

American Family Physician. 2024;110(6):585-591.

Author disclosure: No relevant financial relationships.

This clinical content conforms to AAFP criteria for CME.

Approximately 10% to 20% of the general population has elevated liver chemistry levels, including aspartate and alanine transaminases. Elevated transaminase levels may be associated with significant underlying liver disease and increased risk of liver-related and all-cause mortality. The most common causes of mildly elevated transaminase levels (two to five times the upper limit of normal) are metabolic dysfunction-associated steatotic liver disease (MASLD) and alcoholic liver disease. Uncommon causes include drug-induced liver injury, chronic hepatitis B and C, and hereditary hemochromatosis. Rare causes are alpha1-antitrypsin deficiency, autoimmune hepatitis, and Wilson disease. Extrahepatic causes are celiac disease, hyperthyroidism, rhabdomyolysis, and pregnancy-associated liver disease. Initial laboratory testing assesses complete blood cell count with platelets, blood glucose, lipid profile, hepatitis B surface antigen, hepatitis C antibody, serum albumin, iron, total iron-binding capacity, and ferritin. If MASLD is suspected, the FIB-4 Index Score or NAFLD Fibrosis Score can be used to predict which patients are at risk for fibrosis and may benefit from further testing or referral to a hepatologist. All patients with elevated transaminases should be counseled about moderation or cessation of alcohol use, weight loss, and avoidance of hepatotoxic drugs.

Liver chemistry tests assess liver health and measure levels of alanine transaminase (ALT) and aspartate transaminase (AST). They can identify hepatic inflammation or cholestasis but do not quantify anabolic liver function like serum measurements of albumin or prothrombin time. In general, ALT is a more specific marker of hepatic inflammation because AST is also found in cardiac and skeletal muscle, the kidneys, and the brain.1

SORT: KEY RECOMMENDATIONS FOR PRACTICE

Clinical recommendation Evidence rating Comments
Further evaluation is recommended for all patients with persistent elevated liver transaminase levels or with signs and symptoms of liver disease.16,17 C Population-based retrospective cohort study and prospective cohort study in primary care population
Screen patients with high risk for significant fibrotic liver disease with Fibrosis-4 Index or Nonalcoholic Fatty Liver Disease Fibrosis Score.6,23,24 C Expert consensus recommendations from the American Association of Clinical Endocrinology and the American Association for the Study of Liver Diseases
Lifestyle modifications, including weight loss, a healthy diet, alcohol moderation or cessation, and regular exercise, are recommended for all patients with metabolic dysfunction-associated steatotic liver disease.6 B Recommendation from the American Association for the Study of Liver Diseases based on a meta-analysis of randomized controlled trials
Ask patients with elevated liver transaminase levels about their use of current medications, over-the-counter medications, and supplements.1,8 C Recommendation from the American College of Gastroenterology and the European Association for the Study of the Liver

A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to https://www.aafp.org/afpsort.

ROBERT C. LANGAN, MD, FAAFP, is program director at the St. Luke's Family Medicine Residency-Sacred Heart Campus, Allentown, Penn., and an adjunct professor in the Department of Family and Community Medicine at the Lewis Katz School of Medicine, Temple University, Philadelphia, Penn.

KOURTNI A. HINES-SMITH, MD, is faculty at St. Luke's Family Medicine Residency-Sacred Heart Campus, and an adjunct clinical assistant professor in the Department of Family and Community Medicine at the Lewis Katz School of Medicine, Temple University.

Address correspondence to Robert C. Langan, MD, at robert.langan@sluhn.org.

Author disclosure: No relevant financial relationships.

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