Alpha-Fetoprotein (AFP) Tumor Marker, Serum
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Alpha-fetoprotein (AFP) is a glycoprotein that is produced in early fetal life by the liver and by a variety of tumors including hepatocellular carcinoma, hepatoblastoma, and nonseminomatous germ cell tumors of the ovary and testis (eg, yolk sac and embryonal carcinoma). Most studies report elevated AFP concentrations in approximately 70% of patients with hepatocelllular carcinoma. Elevated AFP concentrations are found in 50% to 70% of patients with nonseminomatous testicular tumors.(1)
AFP is elevated during pregnancy. Persistence of AFP in the mother following birth is a rare hereditary condition.(2) Neonates have markedly elevated AFP levels (>100,000 ng/mL) that rapidly fall to below 100 ng/mL by 150 days and gradually return to normal over their first year.(2)
Concentrations of AFP above the reference range also have been found in serum of patients with benign liver disease (eg, viral hepatitis, cirrhosis), gastrointestinal tract tumors and, along with carcinoembryonic antigen, in ataxia telangiectasia.
The biological half-life of AFP is approximately 5 days.
The follow-up management of patients undergoing cancer therapy, especially for testicular and ovarian tumors and for hepatocellular carcinoma
Often used in conjunction with human chorionic gonadotropin(2)
Alpha-fetoprotein (AFP) levels may be elevated in association with a variety of malignancies or benign diseases.
Failure of the AFP value to return to normal by approximately 1 month after surgery suggests the presence of residual tumor.
Elevation of AFP after remission suggests tumor recurrence; however, tumors originally producing AFP may recur without an increase in AFP.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This assay is intended only as an adjunct in the diagnosis and monitoring of alpha-fetoprotein (AFP)-producing tumors. The diagnosis should be confirmed by other tests or procedures.
AFP is not recommended as a screening procedure for cancer detection in the general population.
Amniotic fluid should not be sent, because this test is only used as a tumor marker. This test is not the correct AFP test for pregnant patients. This test is not intended for the detection of neural tube defects.
Higher values are found in newborns and pregnant women.
Not useful in patients with pure seminoma or dysgerminoma.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Reference values are for nonpregnant subjects only; fetal production of AFP elevates values in pregnant women.
Range for newborns is not available, but concentrations over 100,000 ng/mL have been reported in normal newborns, and the values rapidly decline in the first 6 months of life. (See literature reference: Ped Res 1981;15:50-52.) For further interpretive information, see Alpha-Fetoprotein (AFP) in Special Instructions.
Serum markers are not specific for malignancy, and values may vary by method.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Lange PH, McIntire KR, Waldmann TA, et al: Serum alpha fetoprotein and human chorionic gonadotropin in the diagnosis and management of nonseminomatous germ-cell testicular cancer. N Engl J Med 1976 October;295:1237-1240
2. Tsuchida Y, Endo Y, Saito S, et al: Evaluation of alpha-fetoprotein in early infancy. J Ped Surg 1978 April;13(2):155-162
3. Bosl GJ, Geller NL, Bajorin D: Serum tumor markers and patient allocation to good-risk and poor-risk clinical trials in patients with germ cell tumors. Cancer 1991 March 1;67(5):1299-1304
4. Gregory JJ Jr, Finlay JL: Alpha-fetoprotein and beta-human chorionic gonadotropin: their clinical significance as tumour markers. Drugs 1999 April;57(4):463-467
5. Schefer H, Mattmann S, Joss RA: Hereditary persistence of alpha-fetoprotein. Case report and review of the literature. Ann Oncol 1998 June;9(6):667-672