Alpha-Fetoprotein, Tumor Marker
The AFP tumor marker test quantifies serum alpha-fetoprotein, an oncofetal glycoprotein re-expressed in hepatocellular carcinoma and non-seminomatous germ-cell tumours. It is used to surveil cirrhotic patients at six-month intervals, stage and monitor germ-cell malignancy, and investigate hepatic masses, though 30–40% of early hepatocellular carcinomas are AFP-negative and imaging remains the…
1
Biomarkers
Blood (serum)
Sample
2–3 business days
Turnaround
No
Fasting
What is the AFP test?
The Alpha-Fetoprotein, Tumor Marker test quantifies serum AFP, an oncofetal glycoprotein whose re-expression in adults raises concern for hepatocellular carcinoma or germ-cell malignancy. Practitioners order AFP to surveil patients at high risk for hepatocellular carcinoma — those with cirrhosis from viral hepatitis, alcohol-related liver disease, or metabolic dysfunction-associated steatotic liver disease — to investigate a newly discovered hepatic mass, and to stage and monitor germ-cell tumours. AFP is not diagnostic on its own: even marked elevations require histology or imaging for confirmation, and normal AFP does not exclude cancer. Instead, the marker is interpreted as one component of a broader oncological assessment, serially trended to detect recurrence or monitor response to therapy, and viewed in the context of other tumour markers, liver synthetic function, and imaging findings.
What does the AFP test measure?
Alpha-fetoprotein is a glycoprotein synthesised by the foetal yolk sac, liver, and gastrointestinal tract during early development. In healthy adults serum AFP falls to trace concentrations after birth and remains low throughout life. The protein shares structural homology with albumin and has roles in foetal transport and immune modulation; its re-expression in adults signals hepatocyte regeneration, germ-cell tumour proliferation, or occasionally other malignancies.
Serum AFP is principally a tumour marker for hepatocellular carcinoma and non-seminomatous germ-cell tumours. In hepatocellular carcinoma AFP correlates with tumour burden and is used for surveillance in high-risk cirrhotic patients and for monitoring treatment response, though sensitivity for early-stage disease is modest. In germ-cell tumours AFP elevation identifies non-seminomatous histology, guides prognosis, and tracks therapy. Modest elevations occur in acute or chronic hepatitis, cirrhosis, and pregnancy, so context is essential to interpretation.
Why is the AFP test ordered?
- Surveillance of patients with cirrhosis at six-month intervals, per hepatocellular carcinoma screening guidelines, often paired with hepatic ultrasonography
- Diagnostic evaluation of a newly detected liver mass or focal lesion seen on imaging, interpreted alongside liver enzymes, bilirubin, and cross-sectional imaging
- Staging and prognostic assessment of non-seminomatous germ-cell tumours, measured with beta-hCG and lactate dehydrogenase as part of the germ-cell tumour marker panel
- Monitoring treatment response and detecting recurrence in patients with known AFP-secreting hepatocellular carcinoma or germ-cell tumour, with serial measurements every one to three months depending on clinical trajectory
- Investigation of unexplained hepatomegaly or elevated liver enzymes in patients with viral hepatitis B or C, haemochromatosis, or other chronic liver disease
- Evaluation of metastatic carcinoma of unknown primary when imaging suggests a liver or retroperitoneal source and germ-cell or hepatocellular origin is in the differential
Sample collection and turnaround
Sample type
Blood (serum)
Fasting required
No
Collection method
Venipuncture at patient service centre
Turnaround
2–3 business days
Collection notes
Phlebotomy via Quest at the processing laboratory's draw site; no special preparation required. Women of childbearing age should have pregnancy excluded if AFP is elevated.
Specimen requirements
Minimum 0.5 mL serum. Separate from cells promptly and refrigerate; AFP is stable refrigerated for several days. Note the performing laboratory for serial comparability, as assay platforms differ.
What can affect AFP results?
AFP is produced by the foetal liver and yolk sac, so maternal serum AFP rises during pregnancy and peaks in the second trimester; pregnancy must be excluded when interpreting an elevation in women of childbearing age.
Hepatocyte regeneration and necrosis in viral hepatitis, alcohol-related injury, or cirrhosis can modestly raise AFP, typically to levels below 100 ng/mL, though overlap with malignant ranges exists.
Benign hepatocellular proliferation occasionally produces mild AFP elevation; imaging and histology distinguish these from malignancy.
This rare autosomal recessive condition causes persistent mild AFP elevation unrelated to malignancy or liver disease.
AFP is measured by immunoassay, and results are method-dependent; serial monitoring should use the same laboratory and platform to ensure comparability.
Grossly haemolysed or lipaemic specimens can interfere with immunoassay performance; specimen quality should be noted if results are unexpected.
What do AFP results mean?
Elevated
Hepatocellular carcinoma: values above 200–400 ng/mL are highly suggestive, though lower elevations occur in early disease and some tumours do not secrete AFP. Non-seminomatous germ-cell tumours (yolk sac tumour, embryonal carcinoma, mixed histology): elevation indicates non-seminomatous components and guides prognosis and treatment. Modest elevations (10–100 ng/mL) occur in acute hepatitis, chronic hepatitis, cirrhosis, pregnancy, and occasionally other gastrointestinal malignancies; clinical and imaging context is essential to distinguish regeneration from neoplasia.
Normal
A normal AFP does not exclude hepatocellular carcinoma — 30–40% of early-stage tumours are AFP-negative, so imaging surveillance is the primary screening tool. In germ-cell tumours a normal AFP suggests pure seminoma or other histology; beta-hCG and lactate dehydrogenase should be checked. A normal result in follow-up surveillance is reassuring but must be paired with imaging at guideline intervals.
Reduced
Values below the reference limit are not clinically meaningful; AFP does not have a pathological low threshold.
Note: AFP must be read with imaging, liver synthetic function (albumin, INR), and clinical context. The trajectory of serial values is more informative than a single measurement. Reference intervals and decision thresholds vary by assay and guideline; specify the performing laboratory and document the baseline for serial comparison. Pregnancy, acute hepatitis, and cirrhosis all cause elevations, so AFP alone does not confirm malignancy.
Frequently asked questions
AFP is principally a marker for hepatocellular carcinoma and non-seminomatous germ-cell tumours. Modest elevations occasionally occur with other gastrointestinal malignancies, but imaging and histology remain essential for diagnosis.
How to access the AFP test
The AFP reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.
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Published: October 7, 2026
Last reviewed: October 7, 2026
- Heimbach JK, et al. AASLD guidelines for the treatment of hepatocellular carcinoma. Hepatology. (2018)
- Marrero JA, et al. Diagnosis, staging, and management of hepatocellular carcinoma: 2018 practice guidance by the American Association for the Study of Liver Diseases. Hepatology. (2018)
- Gilligan T, et al. ASCO clinical practice guideline on uses of serum tumor markers in adult males with germ cell tumors. J Clin Oncol. (2010)
- European Association for the Study of the Liver. EASL clinical practice guidelines: management of hepatocellular carcinoma. J Hepatol. (2018)
This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.