Lab Test

Alpha Subunit of Pituitary Glycoprotein Hormones, Serum

Alpha Subunit, HCG, Chorionic Gonadotropin, Alpha-HCG, Alpha-PGH

Test Codes

EPIC: LAB6220, Beaker: XAPGH, MAYO: APGH. This should not be ordered on pregnant patients.

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: One plain Red-top tube.

Send specimen for processing immediately after collection. 

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and freeze (-20°C/-4°F or below).

Preparation for Courier Transport

Transport: 1.0 mL serum, frozen (-20°C/-4°F or below). (Minimum: 0.35 mL)

Rejection Criteria

  • Grossly hemolyzed specimens.
  • Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and freeze (-20°C/-4°F or below).

Transport: 1.0 mL serum, frozen (-20°C/-4°F or below). (Minimum: 0.35 mL) 

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Medical Laboratories, Rochester, MN.

Performed

Sunday.
Results available in 2-8 days.

Reference Range

By report.

Test Methodology

Immunochemiluminescent Assay.

Interpretation

The alpha-subunit of pituitary glycoprotein hormones assay has been called the alpha-human chorionic gonadotropin (hCG) assay. However, the assay measures the alpha-subunit of thyroid-stimulating hormone, in addition to that of hCG.

This assay is not useful as a screening assay for cancer detection in the normal population.

Mayo has analyzed preoperative serum samples from 412 patients with pituitary tumors, and in 27 (6.6%) of these, the values for alpha-PGH were increased. In some cases, this was the only positive serum marker.

Alpha-PGH levels also were measured postoperatively in 21 of the 27 patients with increased values, and these values were consistently lower than preoperative values.

The failure of alpha-PGH to return to normal was associated with residual tumor.

Clinical Utility

Quantitating the alpha-subunit of pituitary glycoprotein hormones has been advocated as a monitoring test to detect the recurrence of tumors in patients who have undergone resection of pituitary adenomas.

CPT Codes

82397
LOINC:  14170-5

Contacts

Last Updated

1/18/2023

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