Alpha-Fetoprotein (AFP), Spinal Fluid

CPT CODE:

USEFUL FOR:

An adjunct in the diagnosis of CNS germinomas and meningealcarcinomatosis
Evaluating germ-cell tumors, including testicular cancer metastatic tothe CNS in conjunction with beta-hCG measurement(1)
An adjunct in distinguishing between suprasellar dysgerminomas andcraniopharyngiomas
A supplement to cerebrospinal fluid cytologic analysis

SPECIMEN REQUIRED:

0.5 mL of spinal fluid. Send specimen frozen in plastic vial.

TRANSPORT TEMPERATURE:

Frozen\Refrig<7 days OK\Ambient NO

CLINICAL INFORMATION:

AFP is an oncofetal glycoprotein, homologous with albumin that isproduced both in early fetal life and in tumors arising from midlineembryonic structures. AFP is synthesized in the yolk sac, liver, andgastrointestinal track of the fetus. In adults, the liver synthesizes AFP.AFP is not normally expressed in the central nervous system (CNS).AFP levels in liver are increased in hepatomas and hematocellularand colon carcinomas, as well as in germ-cell tumors arising fromthe ovaries and non seminomatous germ-cell tumors of the testes,testicular teratocarcinomas, and primary germ-cell tumors arisingwithin the CNS. The presence of germinomas in the CNS andCNS involvement in metastatic cancer and meningeal carcinomatosisresults in increased levels of AFP in cerebrospinal fluid.

CLINICAL INTERPRETATION:

AFP concentrations that exceed the upper end of normal are consistent with the presence of CNS germinoma, meningealcarcinomatosis, or metastatic non seminomatous testicular cancer.AFP is not elevated in the presence of a craniopharyngioma.

REFERENCE VALUES:

<1.5 ng/mL

Reference range for newborns is not available.

For serum ranges, see literature reference: Ped Res 1981;15:50-52.