Lab Dept:

Other Fluids

Test Name:

CHORIONIC GONADOTROPIN, BETA SUBUNIT, CSF

General Information

Lab Order Codes:

BHCC

Synonyms:

Beta hCG CSF; Beta-human Chorionic Gonadotropin CSF; hCG Beta Subunit; hCG Beta subunit Tumor Marker

CPT Codes:

84702 – Gonadotropin, chorionic (hCG), quantitative

Test Includes:

CSF hCG Beta Subunit level measured in IU/L.

Logistics

Test Indications:

Useful for facilitating diagnosis of brain metastases of testicular cancer or extragonadal intracerebral germ cell tumors.

Lab Testing Sections:

Other Fluids - Sendout

Referred to:

Mayo Medical Laboratories (MML Test# BHSF)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1-3 days, test performed Monday - Saturday

Special Instructions:

See Container

Specimen

Specimen Type:

Spinal fluid (CSF)

Container:

Sterile, Leak-proof fluid container

Draw Volume:

Entire specimen

Processed Volume:

1 mL (Minimum: 0.5 mL) spinal fluid

Collection:

Routine spinal fluid collection

Special Processing:

Lab Staff: Mix specimen well and remove aliquot into a sterile, screw-capped round bottom plastic vial. Store and ship at refrigerated temperatures. Specimen is stable 28 days refrigerated. Forward promptly.

Patient Preparation:

None

Sample Rejection:

Specimens other than spinal fluid; mislabeled or unlabeled specimens; gross hemolysis

Interpretive

Reference Range:

<1.0 IU/L

Note: Tumor markers are not specific for malignancy, and values may vary by method.

Critical Values:

N/A

Limitations:

Slight elevations of hCG in spinal fluid may occur in non neoplastic diseases. Measurement of hCG in spinal fluid should not be relied upon exclusively to determine the presence of CNS metastases in patients with germ cell tumors. Specimens should not be collected from patients receiving therapy with high biotin doses (>5 mg/day) until at least 8 hours following the last biotin administration.

Methodology:

Immunometric electrochmiluninescence

References:

Mayo Medical Laboratories Web Page October 2010

Updates:

10/4/2010: Sterile specimen is required.