Alpha-Fetoprotein (AFP) Tumor Marker, Serum
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)
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 hepatocellular 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.
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.
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.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Sturgeon CM, Duffy MJ, Stenman UH, et al: National Academy of Clinical Biochemistry laboratory medicine practice guidelines for use of tumor markers in testicular, prostate, colorectal, breast, and ovarian cancers. Clin Chem 2008 Dec; 54(12):e11-79
2. Blohm ME, Vesterling-Horner D, Calaminus G, et al: Alpha-1-fetoprotein (AFP) reference values in infants up to 2 years of age. Pediatr Hematol Onco 1998 Mar-April;15(2):135-142
3. Milose JC, Filson CP, Weizer AZ, et al: Role of biochemical markers in testicular cancer: diagnosis, staging, and surveillance. Open Access J Urol 2011 Dec 30;4:1-8
4. 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