Alpha-Fetoprotein (AFP) Tumor Marker, Serum

CPT CODE:

USEFUL FOR:

The follow-up management of patients undergoing cancer therapy,especially for testicular and ovarian tumors and for hepatocellularcarcinoma
Often used in conjunction with human chorionic gonadotropin(2)

SPECIMEN REQUIRED:

Draw blood in a plain, red-top tube(s) or a serum gel tube(s). Spin down and send 0.6 mL of serum frozen in plastic vial.

TRANSPORT TEMPERATURE:

Frozen\Refrig <=7 days OK\Ambient <=7 days OK

CLINICAL INFORMATION:

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.

CLINICAL INTERPRETATION:

AFP levels may be elevated in association with a variety of malignancies or benign diseases.  Failure of the AFP value to return to normalby 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.

REFERENCE VALUES:

<6.0 ng/mL

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.