LAB TEST
T3RU test
The T3RU test measures the level of proteins that carry thyroid hormone in the blood. This can help your health care provider interpret the results of T3 and T4 blood tests. Because tests called the free T4 blood test and thyroxine binding globulin (TBG) blood tests are now available, the T3RU test is rarely used these days.
How the Test is Performed
A blood sample is needed.
How to Prepare for the Test
Your provider will tell you if you need to stop taking any medicines before the test that may affect your test result. Do not stop taking any medicine without first talking to your provider. Some medicines that can increase T3RU levels include: Anabolic steroids Heparin Phenytoin Salicylates (high dose) Warfarin Some…
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
This test is done to check your thyroid function. Thyroid function depends on the action of many different hormones, including thyroid-stimulating hormone (TSH), T3, and T4. This test helps check the amount of T3 that TBG is able to bind. TBG is a protein that carries most of the T3 and T4 in the blood. Your provider…
Normal Results
Normal values range from 25% to 38%. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
Higher-than-normal levels may indicate: Kidney failure Overactive thyroid (hyperthyroidism) Nephrotic syndrome Protein malnutrition Chronic liver disease Lower-than-normal levels may indicate: Acute hepatitis (liver disease) Pregnancy Hypothyroidism Use of estrogen, opioids or methadone Abnormal results may also be…
Risks
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. Other risks associated with having blood drawn are slight, but may…
References
Faix JD. Thyroid function testing (thyrotropin, triiodothyronine, and thyroxine). In: Robertson RP, ed. DeGroot's Endocrinology . 8th ed. Philadelphia, PA: Elsevier; 2023:chap 68. Guber HA, Oprea M, Rusell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management…
This is a summary. Read the full article at www.ucsfbenioffchildrens.org (reviewed 28/02/2024).
This page is general information and is not medical advice. It does not replace a registered doctor, and it is not a prescription or a recommendation to use any medicine or test. Prices are listed prices and may change. Always follow the advice of your doctor or pharmacist.