TSI Test in California
TSI Test can be requested without a referral, and this overview covers what to expect. The TSI (Thyroid-Stimulating Immunoglobulin) test is a blood test that measures antibodies that can overstimulate the thyroid gland. It is most often ordered to help diagnose Graves' disease, an autoimmune condition that causes hyperthyroidism, and to monitor treatment response. Across California, part of Pacific, the tsi test can be ordered directly and collected at a certified site — no referral required.
- Sample type
- blood
- Category
- Thyroid
- Turnaround
- 1-3 business days
- Price
- $119
- Referral
- Not required
The TSI (Thyroid-Stimulating Immunoglobulin) test is a blood test that measures antibodies that can overstimulate the thyroid gland. It is most often ordered to help diagnose Graves' disease, an autoimmune condition that causes hyperthyroidism, and to monitor treatment response.
What it measures
- TSI level — The amount of thyroid-stimulating immunoglobulin in the blood; higher levels suggest Graves' disease.
- TSI index — A calculated ratio that compares your TSI level to a reference standard, helping interpret results.
- TSI percentage — Sometimes reported as a percentage of a normal reference range, indicating relative antibody activity.
- Thyroid-stimulating antibody (TSAb) — A related antibody that may be measured alongside TSI to assess thyroid stimulation.
Who it is for
A doctor typically orders a TSI test when you have symptoms of hyperthyroidism, such as unexplained weight loss, rapid heartbeat, or tremors, or when other thyroid tests suggest Graves' disease.
Preparation
No fasting or special preparation is needed for a TSI test. You can eat and drink normally before your blood draw.
Results and what they mean
Results are usually reported as a number or percentage, with a reference range provided by the lab. Your clinician will interpret your TSI level along with your symptoms and other thyroid tests. This information is general and not a substitute for medical advice.
Requesting the TSI Test in California
Order online, choose a certified collection site in California, and review results through a secure portal. No referral is required, and orders are processed confidentially. Because the region is uneven, coastal metros, inland towns, and rural counties with very different access to testing — worth planning around when you book.
Frequently asked questions
What does a high TSI level mean?
A high TSI level often points to Graves' disease, but only your doctor can confirm a diagnosis after reviewing all your test results and symptoms.
Do I need to fast before a TSI test?
No, fasting is not required. You can eat and drink as usual before the blood draw.
How long does it take to get TSI test results?
Results are typically available within 1 to 3 business days, though this can vary by laboratory.
Can TSI levels change over time?
Yes, TSI levels can rise or fall with treatment or over the course of the condition. Your doctor may repeat the test to monitor changes.
TSI Test by city in California
- TSI Test in Los Angeles
- TSI Test in San Francisco
- TSI Test in San Diego
- TSI Test in Riverside
- TSI Test in Sacramento
- TSI Test in San Jose
- TSI Test in Fresno
- TSI Test in Concord
- TSI Test in Bakersfield
- TSI Test in Mission Viejo
- TSI Test in Murrieta
- TSI Test in Long Beach
- TSI Test in Oakland
- TSI Test in Stockton
- TSI Test in Victorville
- TSI Test in Modesto
- TSI Test in Lancaster
- TSI Test in Oxnard
- TSI Test in Indio
- TSI Test in Anaheim
- TSI Test in Antioch
- TSI Test in Santa Rosa
- TSI Test in Santa Ana
- TSI Test in Irvine
- TSI Test in Santa Clarita
- TSI Test in Chula Vista
- TSI Test in Visalia
- TSI Test in Fremont
- TSI Test in San Bernardino
- TSI Test in Thousand Oaks
- TSI Test in Moreno Valley
- TSI Test in Fontana
- TSI Test in Salinas
- TSI Test in Huntington Beach
- TSI Test in Santa Barbara
- TSI Test in Glendale
- TSI Test in Hemet
- TSI Test in Vallejo
- TSI Test in Elk Grove
- TSI Test in Ontario