Alpha Subunit Test
Short Name: Alpha Subunit
Also known as: Alpha Subunit of Glycoprotein Hormones, Alpha SU Test, Glycoprotein Hormone Alpha Subunit, α-Subunit Test
Alpha Subunit Test test available at DNA Labs India for ₹18,000. Uses ECLIA (Electrochemiluminescence Immunoassay) on Serum samples. Results in 2–3 weeks from sample dispatch (samples dispatched by the 7th of each month). Reports will be delivered via online portal, email, or WhatsApp.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Ramarao Paidisetty
Consultant Biochemist · Reg: 21504
Last reviewed: September 7, 2026
Overview
The Alpha Subunit Test is primarily used to evaluate pituitary gland function and to detect pituitary adenomas. It helps clinicians differentiate between TSH-secreting pituitary tumors (thyrotropinomas) and other causes of inappropriate TSH secretion. The test is also useful in identifying gonadotropin-secreting pituitary adenomas and in monitoring treatment response following pituitary surgery or radiation therapy.
- Test Code
- 84
- ICD Code
- E23.6
- Price
- ₹18,000
- Sample Type
- Serum
- Result Time
- 2–3 weeks from sample dispatch (samples dispatched by the 7th of each month). Reports will be delivered via online portal, email, or WhatsApp.
- Fasting Required
- No
- Method
- ECLIA (Electrochemiluminescence Immunoassay)
Sample Collection
No specific fasting is required. However, inform your doctor about all medications and supplements you are taking, especially biotin. A duly filled Test Send Out Consent Form (Form 35) is mandatory before sample collection. Avoid strenuous exercise on the day of the test. If you are pregnant or suspect pregnancy, inform the phlebotomist and your physician.
Method: Venipuncture
Laboratory Analysis
A trained phlebotomist will collect approximately 2 mL of venous blood from a vein in your arm using standard venipuncture technique. The blood sample is drawn into a Red Top (No Additive) tube. Do not use SST gel barrier tubes for this test. The procedure typically takes less than 5 minutes.
Report Delivery
Apply gentle pressure to the puncture site with a cotton ball or bandage for 3–5 minutes. You may resume normal activities immediately. The collected sample will be shipped refrigerated or frozen to the reference laboratory. Reports will be available within 2–3 weeks via online portal, email, or WhatsApp.
Timeline: 2–3 weeks from sample dispatch (samples dispatched by the 7th of each month). Reports will be delivered via online portal, email, or WhatsApp.
Patient Instructions
About This Test
Who Should Get This Test
The Alpha Subunit Test is primarily used to evaluate pituitary gland function and to detect pituitary adenomas. It helps clinicians differentiate between TSH-secreting pituitary tumors (thyrotropinomas) and other causes of inappropriate TSH secretion. The test is also useful in identifying gonadotropin-secreting pituitary adenomas and in monitoring treatment response following pituitary surgery or radiation therapy.
How to Prepare
- Collect 2 mL (minimum 1 mL) serum from 1 Red Top (No Additive) tube
- Do NOT use SST gel barrier tubes
- Allow blood to clot completely before centrifugation
- Ship sample refrigerated (2–8°C) or frozen (−20°C)
- Duly filled Test Send Out Consent Form (Form 35) is mandatory
- Samples are dispatched by the 7th of each month
- Label the tube clearly with patient name, date of birth, and date of collection
Doctor's Notes
Reviewed by Dr Ramarao Paidisetty — MBBS, MD (Biochemistry) · Reg. No. 21504
"The Alpha Subunit test is a valuable adjunct in the evaluation of pituitary disorders. It helps differentiate TSH-secreting pituitary adenomas (thyrotropinomas) from other causes of hyperthyroidism and can aid in identifying gonadotropin-secreting tumors. Elevated alpha subunit levels, especially when the alpha subunit-to-whole-hormone molar ratio is increased, raise suspicion for a pituitary adenoma. This test should always be interpreted alongside pituitary MRI findings and a full hormonal panel for an accurate clinical picture."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Sample collected in SST gel barrier tube
- Hemolyzed, lipemic, or icteric sample
- Sample volume less than 1 mL
- Missing or incomplete Test Send Out Consent Form (Form 35)
- Sample received at room temperature beyond 6 hours
- Improperly labeled or unlabeled sample
Understanding Your Results
Normal (< 1.0 ng/mL)
Alpha subunit levels within the normal reference range. Pituitary glycoprotein hormone secretion is likely functioning normally. Clinical correlation is recommended.
Mildly Elevated (1.0–2.0 ng/mL)
Mildly elevated levels may be seen in primary hypothyroidism, primary hypogonadism, or postmenopausal women. Further evaluation with dynamic pituitary function tests and MRI may be warranted.
Significantly Elevated (> 2.0 ng/mL)
Significantly elevated levels raise strong suspicion for a pituitary adenoma, particularly a thyrotropinoma or gonadotropin-secreting adenoma. Correlation with pituitary MRI and full hormonal panel is essential. Urgent endocrinology consultation is recommended.
Elevated Alpha Subunit-to-Hormone Molar Ratio
An increased molar ratio of alpha subunit to the corresponding intact hormone (TSH, LH, or FSH) is highly suggestive of a pituitary adenoma. This finding warrants further imaging and specialist evaluation.
Consult your endocrinologist if your Alpha Subunit levels are elevated or if you experience symptoms such as persistent headaches, visual field disturbances (especially loss of peripheral vision), unexplained hormonal changes, menstrual irregularities, galactorrhea, fatigue, unexplained weight changes, or signs of thyroid dysfunction. Early evaluation and management of pituitary disorders can significantly improve treatment outcomes.
Limitations
- ⚠Not a standalone diagnostic test; must be interpreted alongside pituitary MRI and full hormonal panel
- ⚠Reference ranges vary with age, sex, and menopausal status
- ⚠Elevated levels may occur in non-neoplastic conditions such as primary hypothyroidism or hypogonadism
- ⚠Sensitivity may be limited for very small microadenomas
- ⚠This is a send-out test and results are not available same-day
Risks & Considerations
- ●Minor bruising or discomfort at the venipuncture site
- ●Rarely, slight swelling or infection at the puncture site
- ●Fainting or lightheadedness in individuals sensitive to blood draws
- ●No significant long-term risks associated with this blood test
Interfering Factors
- ●Biotin supplements may interfere with ECLIA assay results; discontinue at least 72 hours before sampling
- ●Heterophilic antibodies in patient serum can cause false elevation
- ●Pregnancy may cause physiological elevation of alpha subunit due to hCG production
- ●Severe renal impairment may affect clearance and elevate levels
- ●Recent administration of radiopharmaceuticals may interfere with the assay
Compare With Similar Tests
| Test | Alpha Subunit Test | TSH Test | FSH Test | Pituitary MRI |
|---|---|---|---|---|
| Comparison | Alpha Subunit Test |
Frequently Asked Questions
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