Blood Picture in Fatty Liver
In patients with non-alcoholic fatty liver disease (NAFLD), the typical blood picture shows elevated aminotransferases (ALT and AST), elevated gamma-glutamyl transpeptidase (GGT), atherogenic dyslipidemia (elevated triglycerides, total cholesterol, and LDL with decreased HDL), elevated fasting glucose with hyperinsulinemia and insulin resistance, and normal to mildly elevated bilirubin 1, 2, 3.
Liver Enzymes
The most characteristic finding is elevated ALT, which typically exceeds AST in NAFLD patients 3. GGT elevation is also common and correlates with disease severity 3. However, a critical caveat: serum aminotransferase levels do not reliably reflect the spectrum of liver histology 1. Many patients with significant steatohepatitis or even advanced fibrosis may have completely normal liver enzymes 4.
Lipid Profile
Atherogenic dyslipidemia is a hallmark finding, characterized by:
- Elevated triglycerides (strong positive correlation with NAFLD grade) 5, 3, 6
- Elevated total cholesterol 5, 3, 6
- Elevated LDL 6
- Decreased HDL (negative correlation with NAFLD grade) 6
Hypertriglyceridemia represents the strongest lipid predictor for NAFLD presence and progression 3.
Glucose Metabolism
Elevated fasting blood glucose with elevated basal insulin levels and increased HOMA-IR (insulin resistance index) are consistently observed 5, 3. This reflects the tight association between NAFLD and metabolic syndrome. Insulin and triglycerides together serve as prognostic criteria for progression to liver fibrosis with 93.8% specificity and 85.7% sensitivity 5.
Other Blood Parameters
- Total protein and bilirubin: Mildly elevated 5
- Alkaline phosphatase: May be decreased relative to controls 5
- Platelet count: Generally normal unless advanced fibrosis/cirrhosis develops
- Autoantibodies: Elevated in 21% of NAFLD patients (ANA >1:160 or ASMA >1:40), but these do not indicate more advanced disease or atypical features 1
Important Clinical Pitfalls
Do not rely on normal liver enzymes to exclude significant NAFLD. The absence of aminotransferase elevation does not rule out steatohepatitis or even advanced fibrosis 1, 4. This is why risk stratification using FIB-4 score (calculated from age, ALT, AST, and platelet count) is recommended as first-line assessment for identifying patients at risk for advanced fibrosis 2.
Risk Stratification Approach
For patients with suspected NAFLD based on metabolic risk factors:
- Calculate FIB-4 score using age, ALT, AST, and platelet count - this is the most validated and cost-effective first-line tool 2
- FIB-4 <1.3 indicates low probability of advanced fibrosis (NPV 92.7%) 2
- Elevated FIB-4 warrants further evaluation with elastography or Enhanced Liver Fibrosis (ELF) test 2
The combination of body overweight, hypertriglyceridemia, and elevated ALT predicts NAFLD with 98.5% accuracy 3, making this tri-criteria highly useful for clinical diagnosis.
Associated Metabolic Findings
Evaluate for commonly associated comorbidities that influence the blood picture 1:
- Central obesity (elevated BMI correlates strongly with NAFLD severity) 5, 3
- Type 2 diabetes or impaired glucose tolerance
- Hypertension
- Hypothyroidism (check TSH)
- Polycystic ovary syndrome
Patients with NAFLD and multiple metabolic risk factors (especially type 2 diabetes and hypertension) are at highest risk for progressive liver disease and adverse outcomes 1.