AFP
Alpha-Fetoprotein
What it is
Alpha-fetoprotein (AFP) is a glycoprotein produced at high levels by the fetal liver, yolk sac, and gastrointestinal tract during fetal development. AFP is the fetal analogue of albumin — the major protein in fetal serum — and its production is largely silenced after birth, falling to very low levels (typically < 10 ng/mL) in healthy adults. Re-expression of AFP in elevated concentrations in adults occurs in three main contexts: hepatocellular carcinoma (HCC, the most common primary liver cancer), in which AFP is elevated in approximately 60–80% of cases; non-seminomatous germ cell tumours (NSGCTs) — testicular and ovarian yolk sac tumours and mixed teratomas — in which AFP is markedly elevated and used both for diagnosis and treatment monitoring; and, at lower levels, in active liver disease (cirrhosis, hepatitis) reflecting hepatocyte regeneration and damage rather than malignancy. AFP is also used in maternal serum screening during pregnancy (elevated AFP can indicate neural tube defects; low AFP can indicate chromosomal abnormalities) — a completely different clinical context from its oncological use in adults.
Why we measure it
AFP is a protein made in large amounts before birth and at very low levels in healthy adults. Research on AFP centres on liver health. Hepatocellular carcinoma (HCC) is the most common primary liver cancer, and its outlook depends heavily on stage: five-year survival is about 30% when localised and under 3% once it has spread. Its known risk factors — chronic hepatitis B and C, cirrhosis, fatty liver disease with significant scarring, and aflatoxin exposure — relate to markers elsewhere in the Blueprint protocol. International liver societies recommend AFP with ultrasound every six months for people with cirrhosis or chronic hepatitis B. For everyone else, an annual AFP builds a baseline that becomes more meaningful if other results point to liver strain. AFP is not diagnostic on its own — hepatitis and other liver conditions commonly raise it.
Why every 12 months
Annual AFP is appropriate for population-level surveillance in individuals without known liver disease or identified risk factors. In individuals with cirrhosis, chronic hepatitis B, or other established HCC risk factors, more frequent monitoring (every 6 months) alongside liver ultrasound is recommended by hepatology societies. The annual draw provides the baseline and trend data that contextualise any future elevation.
What movement means
The standard upper reference limit for AFP in adults is 10 ng/mL, though some laboratories use 7 or 8 ng/mL. Levels between 10 and 20 ng/mL are a 'grey zone' with overlap between active liver disease and early HCC. Levels above 400–500 ng/mL in an individual with a liver mass are strongly associated with HCC. Testicular NSGCT typically produces AFP in the hundreds to thousands of ng/mL range.
Normal
< 10 ng/mL
Within the standard reference range for healthy adults. Trend across annual draws is informative — research treats a sustained rise, particularly in people with liver conditions or hepatitis, as worth following.
Standard laboratory reference ranges — vary by assay method
Borderline
10 – 20 ng/mL
Mild elevation. Research notes this range is often associated with liver inflammation or scarring (hepatitis, cirrhosis) rather than cancer. Many conditions raise AFP, and it is not diagnostic on its own. Discuss with a registered medical practitioner.
Bruix J, Sherman M, American Association for the Study of Liver Diseases, Hepatology, 2011
Elevated
> 20 ng/mL
Above the reference range. International liver society criteria use AFP alongside liver imaging, and treat very high levels (above 400 ng/mL) with a liver mass as strongly associated with hepatocellular carcinoma. AFP is not diagnostic on its own. Discuss with a registered medical practitioner.
European Association for the Study of the Liver (EASL) HCC Clinical Practice Guidelines, Journal of Hepatology, 2018
This page summarises published research for general education. It is not medical advice and does not interpret individual results. Discuss your results with a registered medical practitioner.
In the protocol
References
- 1.
Bruix J, Sherman M; American Association for the Study of Liver Diseases. “Management of Hepatocellular Carcinoma: An Update.” Hepatology. 2011.
- 2.
European Association for the Study of the Liver. “EASL Clinical Practice Guidelines: Management of Hepatocellular Carcinoma.” Journal of Hepatology. 2018.
- 3.
Deugnier Y, Turlin B. “Pathology of Hepatic Iron Overload.” World Journal of Gastroenterology. 2007.
- 4.
International Germ Cell Cancer Collaborative Group. “International Germ Cell Consensus Classification: A Prognostic Factor-Based Staging System for Metastatic Germ Cell Cancers.” Journal of Clinical Oncology. 1997.