Test Overview
Clinical Utility
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
Method
Chemiluminescent immunoassay (CLIA)
Result Included
α-Glycoprotein Subunit
Aliases/Synonyms
Alpha-Glycoprotein subunit; a-subunit; a-glycoprotein subunit
Specimen
Containers
Preferred Containers
Gold top (clot activator & gel)
Acceptable Containers
Red top (no additive)
Volume
Sample Volume
1 mL
Minimum Volume
0.35 mL
Specimen Comment
This test should not be ordered on pregnant patients.
Collection & Handling
Handling Information
Store and send frozen.
Stability
| Refrigerated | Frozen |
|---|---|
| 7 days | 90 days |
Rejection Criteria
| Criteria | Specification |
|---|---|
| Hemolysis | Gross |
Performance & Interpretation
Turnaround Time
11 days
Specimen Retention Time
90 days
Results
-
α-Glycoprotein Subunitng/mLPediatric Reference Ranges
0 - 5 d: ≤50
6 days - 12 w: ≤10
3 m - 17 y: ≤1.2
Tanner Stage II - IV*: ≤1.2
Adult Reference Ranges
Males: ≤0.5
Female Premenopausal: ≤1.2
Female Postmenopausal: ≤1.8
Comment
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.
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 renal 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.
Referral Location
Out-of-Country
Interface & Setup
HL7 Interface Codes
| Order Code | Result Name | Result Codes | Units |
|---|---|---|---|
| AGPS | AlphaSubunit Pituitary Tumor Marker | 20491 | ng/mL |
Test Version
Last Updated
2024-02-20