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Thyroglobulin Antibody (Thyroid-Stimulating Immunoglobulin, TSI) – Serum

Published: August 9, 2026Updated: August 16, 2026

This test measures antibodies that may stimulate your thyroid gland, often linked to conditions like Graves’ disease.

Quick summary

["TSI antibodies can help diagnose autoimmune thyroid disorders affecting your thyroid function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
87556-7
Short code
Thyroglob + thyroperox Ab Pnl SerPl
Synonyms
Thyroglob + thyroperox Ab Pnl SerPl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms of hyperthyroidism (e.g., rapid heartbeat, weight loss, anxiety) or if you have a history of Graves’ disease or other autoimmune thyroid conditions. It may also be used to monitor treatment in some cases.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. Avoid caffeine or alcohol for 1 hour before testing if instructed.

What the Test Results Mean

Results are qualitative (positive/negative) and indicate whether your body produces TSI antibodies. Elevated levels suggest possible Graves’ disease or other autoimmune thyroid stimulation.

Common Conditions Linked to TSI Antibodies

High TSI antibody levels are most strongly associated with Graves’ disease, an autoimmune disorder causing overactive thyroid function. Rarely, they may appear in other thyroid-related autoimmune conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

TSI antibodies are critical for diagnosing Graves’ disease, as they directly stimulate thyroid hormone production. They help differentiate autoimmune thyroid disorders from other causes of hyperthyroidism.

Short name

TSI Antibody (Thyroid-Stimulating Immunoglobulin)

Frequently asked questions

What triggers this test?
Your doctor may recommend it if you have symptoms like unexplained weight changes, fatigue, or an enlarged thyroid, or if you have a family history of autoimmune thyroid disease.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab.
Can diet affect TSI antibody levels?
Diet alone does not directly influence TSI antibody levels, but avoiding caffeine or alcohol before testing may improve accuracy.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy