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HelpTest Code MISC2MAYOBHSF Beta-Human Chorionic Gonadotropin, Quantitative, Spinal Fluid
Reporting Name
Chorionic Gonad Beta-Subunit QN,CSFUseful For
Aiding in the diagnosis of brain metastases of testicular cancer or extragonadal intracerebral germ cell tumors
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
CSFSpecimen Required
Patient Preparation: For 12 hours before specimen collection, do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Container/Tube: Sterile vial
Specimen Volume: 1 mL
Collection Instructions: Submit specimen from collection vial 1.
Specimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 28 days | |
| Ambient | 14 days | ||
| Frozen | 14 days |
Reference Values
<1.0 IU/L
Day(s) Performed
Monday through Saturday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84702
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| BHSF | Chorionic Gonad Beta-Subunit QN,CSF | 14041-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| BHSF | Chorionic Gonad Beta-Subunit QN,CSF | 14041-8 |
Clinical Information
Human chorionic gonadotropin (hCG) is synthesized during pregnancy by syncytiotrophoblast cells. hCG may also be produced by neoplastic cells of testicular tumors (seminomas or nonseminomas), ovarian germ cell tumors, gestational trophoblastic disease, choriocarcinoma, and various nontrophoblastic tumors including breast, ovarian, pancreatic, cervical, gastric, and hepatic cancers.
Measurement of hCG is used as an adjunct in the diagnosis of germ cell tumors. The presence of hCG in cerebrospinal fluid (CSF) is suggestive of tumor presence. Pure germinomas are associated with low hCG concentrations in both serum and CSF. A subset of nongerminomatous germ cell tumors contain syncytiotrophoblastic giant cells. These tumors are associated with moderately increased hCG concentrations (<1000 IU/L) in the serum and/or CSF, and the survival rate in patients suffering these tumors is worse than that of patients with pure germinomas. In contrast, choriocarcinomas, another subset of nongerminomatous germ cell tumors, are associated with very high hCG concentrations (>1000 IU/L) in both serum and CSF. Quantification of the hCG in CSF can be important in guiding treatment and monitoring response to treatment of these tumors.
The combination of the specific antibodies used in the Roche Beta hCG immunoassay recognize the holo-hormone, "nicked" forms of hCG, the beta-core fragment, and the free beta-subunit.
Interpretation
Elevated levels of human chorionic gonadotropin in spinal fluid indicate the probable presence of central nervous system metastases or recurrence of tumor in patients with germ cell tumors, including patients with testicular cancer or choriocarcinoma.
Method Description
The Roche human chorionic gonadotropin (hCG) assay is a 2-site immunometric sandwich assay using electrochemiluminescence detection. Patient specimen, biotinylated monoclonal hCG-specific antibody, and monoclonal hCG-specific antibody labeled with a ruthenium react to form a complex. Streptavidin-coated microparticles act as the solid phase to which the complex becomes bound. Voltage is applied to the electrode inducing a chemiluminescent emission from the ruthenium, which is then measured against a calibration curve to determine the amount of hCG in the patient specimen.(Package insert: Elecsys HCG+B. Roche Diagnostics; V1.0. 10/2020)
Report Available
1 to 3 daysReject Due To
| Hemolysis | Reject |
Method Name
Electrochemiluminescent Immunoassay (ECLIA)
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.