What evaluations should be performed in an otherwise healthy 16‑year‑old with elevated liver function tests?

Evaluation of Elevated LFTs in an Otherwise Healthy 16-Year-Old

In an otherwise healthy 16-year-old with elevated liver function tests, you should perform a comprehensive liver aetiology screen that includes specific pediatric considerations: abdominal ultrasound, hepatitis B surface antigen, hepatitis C antibody (with PCR if positive), autoimmune markers (anti-mitochondrial, anti-smooth muscle, antinuclear, and anti-liver kidney microsomal antibodies), serum immunoglobulins, coeliac antibodies, alpha-1-antitrypsin level, and caeruloplasmin (since age >3 years), along with a detailed medication history including over-the-counter drugs, supplements, and herbal products 1.

Initial Clinical Assessment

Before ordering tests, obtain:

• Detailed medication history: All prescription drugs, over-the-counter medications, vitamins, herbal supplements, and performance-enhancing substances (common in adolescents)
• Alcohol and substance use history: Despite age, assess honestly and confidentially
• Family history: Wilson's disease, hemochromatosis, autoimmune conditions, metabolic disorders
• Metabolic risk factors: BMI, signs of insulin resistance, acanthosis nigricans
• Symptoms: Fatigue, pruritus, jaundice, abdominal pain, weight changes

Review any previous liver test results to determine if this is acute or chronic elevation 1.

Pediatric-Specific Liver Aetiology Screen

The 2018 Gut guidelines specifically modify the adult screening panel for children 1:

Core Testing Panel:

• Abdominal ultrasound (assess for steatosis, structural abnormalities, biliary disease)
• Viral hepatitis: Hepatitis B surface antigen, hepatitis C antibody with reflex PCR
• Autoimmune markers:
  • Anti-mitochondrial antibody
  • Anti-smooth muscle antibody
  • Antinuclear antibody
  • Anti-liver kidney microsomal (anti-LKM) antibody (pediatric-specific)
  • Serum immunoglobulins
• Coeliac antibodies (tissue transglutaminase IgA with total IgA)
• Alpha-1-antitrypsin level
• Caeruloplasmin (for Wilson's disease screening, appropriate at age 16)
• Complete blood count (if not done in previous 12 months)

Important Pediatric Considerations:

Ferritin and transferrin saturation may not be indicated in the initial pediatric screen 1. However, if there are specific risk factors for hemochromatosis (family history, unexplained symptoms), these can be added.

Any abnormalities in metabolic screening should be discussed with an inherited metabolic disease specialist 1.

Pattern Recognition Matters

The degree of elevation does not necessarily indicate clinical significance—the specific pattern and clinical context are more important 1:

• Hepatocellular pattern (ALT/AST predominant): Consider viral hepatitis, autoimmune hepatitis, Wilson's disease, drug-induced liver injury, NAFLD
• Cholestatic pattern (ALP/GGT predominant): Consider primary sclerosing cholangitis, drug-induced cholestasis, biliary obstruction
• Isolated bilirubin elevation: If predominantly unconjugated with normal other tests, likely Gilbert's syndrome (benign, requires reassurance only) 1

Critical Pitfalls to Avoid

1. Don't assume NAFLD without excluding other causes: Studies show that 11.6-28.4% of adolescents presumed to have NAFLD actually have alternative diagnoses when properly investigated 2, 3. This is a common diagnostic error.

2. Don't dismiss mild elevations: Even mild ALT elevations are associated with increased liver-related mortality, and pediatric liver diseases are often clinically silent 2, 4, 5.

3. Don't skip Wilson's disease screening: At age 16, Wilson's disease must be considered. Caeruloplasmin is essential in this age group 1.

4. Don't forget autoimmune hepatitis: Anti-LKM antibodies are specifically important in pediatric autoimmune hepatitis and are not part of standard adult panels 1.

Follow-Up Strategy

If initial screen is negative but LFTs remain elevated:

• Repeat testing in 3-6 months to confirm persistence
• If persistently abnormal (≥6 months) or markedly elevated at any point, refer to pediatric gastroenterology/hepatology 6, 1
• Studies show that only 29% of children with unexplained elevated LFTs receive adequate follow-up, representing missed diagnostic opportunities 2

If screen reveals abnormalities:

• Discuss metabolic findings with inherited disease specialist
• Refer to pediatric hepatology for further evaluation including possible liver biopsy if diagnosis remains unclear 1, 5

When to Refer Urgently

Immediate referral to pediatric hepatology if:

• Synthetic dysfunction (elevated INR, low albumin)
• Conjugated hyperbilirubinemia
• Clinical signs of liver failure or portal hypertension
• Markedly elevated transaminases (>10x upper limit of normal)
• Any concerning symptoms or signs on examination 1

The key principle: investigate comprehensively from the start rather than assuming NAFLD in an adolescent, as this age group has significant risk for treatable conditions like Wilson's disease, autoimmune hepatitis, and viral hepatitis that require specific interventions to prevent morbidity and mortality 2, 3.