Tumor markers
Alpha-fetoproteinAFP
Fetal albumin; HCC and germ-cell tumor surveillance.
Sample
Serum
Clinical reference range
— to 10 ng/mL
Non-pregnant adult
Conv: —–10 ng/mL
Biology
What it measures
Major fetal serum protein (replaced by albumin postnatally). Re-expressed in HCC and yolk-sac tumors.
Clinical use
Why we order it
HCC surveillance every 6 mo in cirrhotics with ultrasound. Testicular germ-cell staging/monitoring.
Differential
Causes of abnormal values
Causes of HIGH
- ↑HCC (>400 ng/mL highly suggestive in a cirrhotic)
- ↑Non-seminomatous germ-cell tumor
- ↑Pregnancy (NTDs ↑, Down syndrome ↓)
- ↑Active hepatitis/cirrhosis
Pitfalls
Pre-analytic & interpretation traps
- !Pure seminoma does NOT produce AFP — an elevated AFP rules out pure seminoma.