Exercise-induced increases in "liver function tests" in a healthy adult male: Is there a knowledge gap in primary care?

A routine clinical assessment in a 39-year-old male revealed liver function tests at 1.4-2.3 times the normal limit. He was asymptomatic, had no personal/family history of liver disease, and did not drink or use recreational drugs. He was in good physical condition and engaged in regular running and resistance exercise. Negative workup included tests for hepatitis A, B, and C, M-proteins, and antimitochondrial antibodies. Abdominal ultrasound was unremarkable. The patient was referred to a gastroenterologist who ordered repeat liver function tests (LFTs) and a liver biopsy. Before his follow-up assessment the patient abstained from exercise for seven days, after which all LFTs had normalized. The abnormal liver panel was thus likely due to exercise-induced muscle damage and/or changes in hepatocyte membrane permeability. Importantly, the diagnostic pathway did not include any assessment of muscle biomarkers (e.g., creatine kinase) or the patient's exercise training habits. This case highlights a knowledge gap in primary care regarding the possible causes of LFT abnormalities in young adults.