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HelpTest Code APGH Alpha-Subunit Pituitary Tumor Marker, Serum
Reporting Name
AlphaSubunit Pituitary Tumor MarkerUseful For
Adjunct in the diagnosis of pituitary tumors
As part of the follow-up of treated pituitary tumor patients
Differential diagnosis of thyrotropin-secreting pituitary tumor versus thyroid hormone resistance
Differential diagnosis of constitutional delay of puberty versus hypogonadotrophic hypogonadism
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumOrdering Guidance
This test should not be ordered on pregnant patients.
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial
Specimen Minimum Volume
0.35 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 90 days |
| Refrigerated | 7 days |
Reference Values
PEDIATRIC
≤5 days: ≤50 ng/mL
6 days-12 weeks: ≤10 ng/mL
3 months-17 years: ≤1.2 ng/mL
Tanner II-IV*: ≤1.2 ng/mL
ADULTS
Males: ≤0.5 ng/mL
Premenopausal females: ≤1.2 ng/mL
Postmenopausal females: ≤1.8 ng/mL
Pediatric and adult reference values based on Mayo studies.
*Puberty onset (transition from Tanner stage I to Tanner stage II) occurs for boys at a median age of 11.5 (±2) years and for girls at a median age of 10.5 (±2) years. There is evidence that it may occur up to 1 year earlier in obese girls and in African American girls. For boys, there is no proven relationship between puberty onset and body weight or ethnic origin. Progression through Tanner stages is variable. Tanner stage V (adult) should be reached by age 18.
Day(s) Performed
Sunday
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
82397
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| APGH | AlphaSubunit Pituitary Tumor Marker | 14170-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 9003 | AlphaSubunit Pituitary Tumor Marker | 14170-5 |
Cautions
False-positive elevations in serum free alpha-subunit levels may be seen in some women if blood specimens are drawn within 24 hours of ovulation.
Patients with end-stage kidney failure may have serum free alpha-subunit concentrations of up to 6-times the upper limit of reference range.
Elevated alpha-subunit results on patients with elevated thyrotropin (TSH) should be interpreted with caution due to TSH cross-reactivity with the assay.
Assisted reproduction involving ovarian hyperstimulation or in vitro fertilization may be associated with the elevation in serum free alpha-subunit levels.
Pregnancy is associated with very substantial, physiological elevations in serum free alpha-subunit levels, paralleling chorionic gonadotropin (hCG) secretion. This test should not be ordered on pregnant patients.
Thyrotropin-releasing hormone and gonadotropin releasing hormone testing are not performed in the laboratory, but in specialized clinical testing units under the supervision of a physician.
Report Available
2 to 8 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
NY State Approved
YesMethod Name
Immunochemiluminescent Assay
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.