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HelpTest Code IEHCG Interference Evaluation Heterophile, Beta-Human Chorionic Gonadotropin, Serum
Reporting Name
Interference Eval, Heterophile, HCGPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Evaluating suspected interference from heterophile antibodies causing a falsely elevated human chorionic gonadotropin result
This test is not to be used for pregnancy testing.
Method Name
HCGQN: Electrochemiluminescent Immunoassay
HCGAM: Immunoenzymatic Assay
Ordering Guidance
If "HCG Total OB" or pregnancy is indicated, order THCG / Human Chorionic Gonadotropin (hCG), Quantitative, Pregnancy, Serum.
Specimen 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.
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 2.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Type
SerumSpecimen Minimum Volume
1.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 90 days | ||
| Ambient | 7 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
BETA-HUMAN CHORIONIC GONADOTROPIN, QUANTITATIVE, SERUM
Children(1,2)
Males
Birth-3 months: ≤50 IU/L*
>3 months-<18 years: <1.4 IU/L
Females
Birth-3 months: ≤50 IU/L*
>3 months-<18 years: <1.0 IU/L
Pediatric reference values based on:
1. Chen RJ, Huang SC, Chow SN, Hsieh CY: Human chorionic gonadotropin pattern in maternal circulation. Amniotic fluid and fetal circulation in late pregnancy. J Reprod Med. 1993;38(2):151-154
2. Schneider DT, Calaminus G, Gobel U: Diagnostic value of alpha 1-fetoprotein and beta-human chorionic gonadotropin in infancy and childhood. Pediatr Hematol Oncol. 2001;18(1):11-26
*Human chorionic gonadotropin (hCG), produced in the placenta, partially passes the placental barrier. Newborn serum beta-hCG concentrations are approximately 1/400th of the corresponding maternal serum concentrations, resulting in neonate beta-hCG levels of 10-50 IU/L at birth. Clearance half-life is approximately 2 to 3 days. Therefore, by 3 months of age, levels comparable to adults should be reached.
Adults (97.5th percentile)
Males: <1.4 IU/L
Females
Premenopausal, nonpregnant: <1.0 IU/L
Postmenopausal: <7.0 IU/L
HUMAN CHORIONIC GONADOTROPIN, ALTERNATIVE METHOD
Males
Birth-3 months: Not established
>3 months-49 years: <0.6 IU/L
50 years-80 years: <1.6 IU/L
>80 years: Not established
Females
Birth-3 months: Not established
>3 months-40 years: <0.6 IU/L
41 years-50 years: <6.2 IU/L
51 years-150 years: <7.8 IU/L
Interpretation
Specimens are evaluated for potential heterophile antibody interference in the Roche Elecsys total beta-human chorionic gonadotropin (hCG) immunoassay. Evaluation consists of pretreatment with commercial heterophile antibody blocking tube reagents, serial dilution of the sample, and testing on an alternate platform (Beckman Coulter DxI). The presence of heterophile antibody interference in the Roche Elecsys assay is not suspected when the results from the pretreatment, serial dilution, and the alternative platform agree within 20% of the original result.
The presence of heterophile antibody interference in the Roche Elecsys assay is suspected when 1 or more of the following are observed: a significant decrease in hCG (>20%) upon treatment of the sample with heterophile antibody blocking reagents, lack of linearity upon serial dilutions, or a significant difference in hCG concentration on the alternate platform. When a heterophile antibody interference affecting the Roche Elecsys assay is suspected, the hCG results from this assay are considered false-positive results and should not be used in clinical management.
Heterophile reagent blocking tubes (HBT-Scantibodies) contain a unique blocking reagent composed of specific binders, which inactivate heterophilic antibodies. Once the specific binders have bound to the heterophilic antibodies, the antibodies are no longer able to cause immunoassay interference. Blocking agents do not inhibit all heterophilic antibodies completely and cannot be used to rule out the presence of heterophile antibody interference.
For patients with apparent serum hCG concentrations greater than 15 to 20 IU/L, hCG should also be detectable in urine if it is truly elevated. Failure to detect urinary hCG in such patients can support the suspicion of a false-positive serum hCG test.
After delivery, miscarriage, or pregnancy termination, hCG levels fall with a half-life of 24 to 36 hours, until prepregnancy levels are reached. An absent or significantly slower decline is seen in patients with retained products of conception.
Gestational trophoblastic disease (GTD) is associated with very considerable elevations of hCG, usually above 2 multiples of the median for gestational age persisting, or even rising beyond, the first trimester.
Serum hCG levels are elevated in approximately 40% to 50% of patients with nonseminomatous testicular cancer and 20% to 40% of patients with seminoma. Markedly elevated levels of hCG (>5000 IU/L) are uncommon in patients with pure seminoma and indicate the presence of a mixed testicular cancer.
Ovarian germ cell tumors (approximately 10% of ovarian tumors) display elevated hCG levels in 20% to 50% of cases.
Teratomas in children may overproduce hCG, even when benign, resulting in precocious pseudopuberty. Levels may be elevated to similar levels as seen in testicular cancer.
Among nonreproductive tumors, hepatobiliary tumors (hepatoblastomas, hepatocellular carcinomas, and cholangiocarcinomas) and neuroendocrine tumors (eg, islet cell tumors and carcinoids) are those most frequently associated with hCG production.
Many hCG-producing tumors also produce other embryonic proteins/antigens, in particular alpha fetoprotein (AFP). Therefore, AFP should also be measured in the diagnostic workup of such neoplasms.
Complete therapeutic response in hCG-secreting tumors is characterized by a decline in hCG levels with an apparent half-life of 24 to 36 hours and eventual return to concentrations within the reference range. GTD and some tumors may produce hyperglycosylated hCG with a longer half-life, but an apparent half-life of greater than 3 days suggests the presence of residual hCG-producing tumor tissue.
A rise in hCG levels above the reference range in patients with hCG-producing tumors that had previously been treated successfully suggests possible local or distant metastatic recurrence.
Day(s) Performed
Monday through Saturday
Report Available
2 to 4 daysTest Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84702 x 2
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| IEHCG | Interference Eval, Heterophile, HCG | 99306-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| HCGQN | Beta-HCG, Quantitative, S | 21198-7 |
| HCGAM | HCG, Alternative Method, S | 21198-7 |
| HCGIF | HCG, Interference Heterophile | 99307-1 |
| HCGIN | HCG, Interpretation | 77202-0 |
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| HCGII | HCG, Interference Interpretation | No | Yes |
| HCGQN | Beta-HCG, Quantitative, S | Yes, (order BHCG) | Yes |
| HCGAM | HCG, Alternative Method, S | No | Yes |
Testing Algorithm
This heterophile antibody evaluation consists of pretreatment with commercial heterophile antibody blocking reagents, testing on an alternate platform, and serial dilution of the sample.