간 기능 검사: 간 수치 상승, 언제 걱정해야 할까
빠른 답변: 간 기능 검사(Liver Function Tests)는 간세포 손상 시 방출되는 효소를 측정합니다. 핵심 지표: ALT(알라닌 아미노전이효소, 정상 7-56U/L, 간 특이성 가장 높음), AST(아스파르테이트 아미노전이효소, 정상 10-40U/L, 심근·골격근 손상에서도 상승), ALP(알칼리성 인산분해효소, 정상 44-147U/L, 담도 질환 표지자), GGT(감마글루타밀전이효소, 알코올성 간질환에 민감), 빌리루빈, 알부민. 경미한 상승(<3배): 비알코올성 지방간(가장 흔함, 성인의 25%), 약물성(아세트아미노펜, 스타틴), 알코올, 비만. 중등도 상승(3-10배): 바이러스 간염, 자가면역 간염, 약물 독성. 중증 상승(>10배): 급성 바이러스 간염, 약물/독소에 의한 급성 간 손상, 허혈성 간염. AST/ALT 비율 >2는 알코올성 간질환 시사. 지속적 이상 시 추가 검사: 바이러스 간염 선별, 간 초음파, 페리틴 등을 권장합니다.
Disclaimer: 이 내용은 정보 제공 목적이며 의료 조언이 아닙니다. 전체 면책조항.
What Do Liver Function Tests Measure?
Despite the name, "liver function tests" primarily measure liver cell damage rather than liver function. True functional tests include albumin, bilirubin, and INR. The standard LFT panel includes:
- ALT (Alanine Aminotransferase): Most specific marker for liver cell damage. Normal: 7-56 U/L. Primarily found in the liver. Even mild elevation warrants attention.
- AST (Aspartate Aminotransferase): Found in liver, heart, muscle, and kidney. Normal: 10-40 U/L. Less specific than ALT — elevated AST with normal ALT may indicate muscle or heart injury rather than liver disease.
- ALP (Alkaline Phosphatase): Elevated in bile duct obstruction (cholestatic pattern) and bone disease. Normal: 44-147 U/L. Must be interpreted with GGT to distinguish liver from bone source.
- GGT (Gamma-Glutamyl Transferase): Sensitive but non-specific. Elevated by alcohol, medications, and bile duct disease. Useful for confirming liver source of elevated ALP.
- Bilirubin: Product of red blood cell breakdown, processed by the liver. Normal total bilirubin: 0.1-1.2 mg/dL. Elevated levels cause jaundice (yellowing of skin/eyes).
- Albumin: Protein produced by the liver. Low albumin (below 3.5 g/dL) indicates impaired liver synthetic function — a sign of advanced liver disease.
Upload your liver panel to WAYJET's Medical Report Analyzer for pattern recognition and severity assessment.
What Causes Elevated Liver Enzymes?
The interpretation depends on the pattern and magnitude of elevation:
Mild elevation (1-3x upper limit):
- Non-alcoholic fatty liver disease (NAFLD): The most common cause of mildly elevated ALT in developed countries, affecting 25% of adults globally. Associated with obesity, metabolic syndrome, and insulin resistance.
- Medications: Statins (2-3% incidence), acetaminophen (especially above 4g/day), NSAIDs, antibiotics, antifungals, and many others
- Alcohol use: Classic pattern is AST:ALT ratio above 2:1 (AST is disproportionately elevated)
- Muscle injury: Intense exercise can elevate AST (and occasionally ALT) for 24-48 hours
Moderate elevation (3-10x upper limit):
- Acute viral hepatitis (A, B, C, EBV, CMV)
- Autoimmune hepatitis
- Drug-induced liver injury (DILI)
- Biliary obstruction
Severe elevation (above 10x upper limit):
- Acute viral hepatitis (can reach 1,000-5,000+ U/L)
- Acetaminophen toxicity
- Ischemic hepatitis (shock liver)
- Acute biliary obstruction
When Should You Worry About Elevated Liver Tests?
Not all elevated liver enzymes require immediate concern, but certain scenarios warrant prompt action:
Repeat and investigate if:
- ALT above 2x upper limit on a single test — retest in 2-4 weeks
- Persistent elevation (2+ tests showing elevated ALT over 6 months)
- Elevation accompanied by fatigue, abdominal pain, or jaundice
Seek medical evaluation promptly if:
- ALT or AST above 5x upper limit (above 200 U/L)
- Elevated bilirubin with elevated ALT (indicates significant liver injury)
- Low albumin (below 3.5 g/dL) or prolonged INR (indicates impaired liver function)
- New jaundice (yellow skin or eyes)
For NAFLD (the most common cause), evidence-based management includes:
- Weight loss of 7-10% body weight (reduces liver fat by 50-80% per MRI studies)
- Mediterranean diet (shown to reduce liver fat independent of weight loss)
- Regular exercise (150+ minutes moderate intensity per week)
- Avoid alcohol completely if liver enzymes are elevated
- Consider liver ultrasound or FibroScan to assess for fibrosis
자주 묻는 질문
Can exercise cause elevated liver enzymes?
Yes, intense exercise (especially eccentric exercise like downhill running or heavy weightlifting) can elevate AST and occasionally ALT for 24-72 hours due to muscle damage releasing these enzymes. If your liver enzymes were mildly elevated, consider whether vigorous exercise in the 48 hours before blood work could explain the result. Retest after 3-5 days of rest if suspicious.
Is fatty liver disease serious?
NAFLD ranges from simple steatosis (fat accumulation without inflammation — generally benign) to NASH (non-alcoholic steatohepatitis — fat with inflammation and liver cell damage). NASH can progress to fibrosis, cirrhosis, and liver cancer in 10-20% of cases over 10-20 years. Early detection and lifestyle intervention is critical to prevent progression.
Should I stop taking my medication if liver enzymes are elevated?
Never stop a prescribed medication based on elevated liver enzymes without consulting your doctor. Mild elevations (below 3x upper limit) on statins, for example, are often transient and do not require discontinuation. Your doctor will weigh the benefits of the medication against the liver enzyme elevation and may adjust the dose or monitor more frequently rather than discontinuing.
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