Triiodothyronine Uptake
T3U
Description
"Triiodothyronine Uptake (T3 Uptake)" test measures how well your blood’s binding proteins interact with thyroid hormones, offering insight into hormonal availability. It’s often paired with other tests to diagnose conditions like hypothyroidism or hyperthyroidism. Low uptake may suggest protein or hormone imbalances, while high uptake may reflect overactivity. Doctors recommend this test when symptoms such as irregular heartbeat, tiredness, or weight changes arise. Results help guide hormone-related decisions and support better thyroid and metabolic care.
Category
Hormones
Procedure
Invasive
Sample Type
Blood – Serum
Units
Percentage
Procedure Category
Blood Draw
Test Group
Complete Thyroid Group
Test Group Description
Complete Thyroid Group: A comprehensive array of tests for a thorough evaluation of thyroid function, providing detailed insights into thyroid health and associated conditions.
Optimal Range
For All Individuals:
Conventional Unit: 28–38%
SI Unit: Not Applicable
Normal Range
For All Individuals:
Conventional Unit: 25–35%
SI Unit: Not Applicable
Results That Differ From The Norm (Direct and Indirect Causes)
Increased levels may indicate:
Estrogen-producing tumors
Estrogen replacement therapy
Genetic factors
Hyperthyroidism (Overactive thyroid function)
Medications (such as oral contraceptives)
Pregnancy
Decreased levels may...
Key Reasons For Testing
Thyroid Function Assessment: Evaluates thyroid hormone production, aiding in diagnosing thyroid disorders.
Hyperthyroidism Diagnosis: Abnormal uptake levels help diagnose and monitor hyperthyroidism.
Hypothyroidism Monitoring: Assesses hormone replacement therapy efficacy in hypothyroid patients.
Thyroid Hormone Binding Capacity: Reflects thyroid-binding protein capacity, offering insights into hormone transport.
Assessment of Thyroid Hormone Availability: Measures hormone availability for cellular uptake and utilization.
Health Status Conditions It May Be Used To Assess
Currently, this test is not directly associated with any conditions listed on the Health Status page. However, it may be included as part of a broader set of tests linked to specific health conditions.
Some Prominent Medical Labs That May Offer This Test
Please note that this particular test has not been associated with any of the listed prominent medical labs. We recommend enquiring with your private physician or nearest hospital to determine where this specific test can be performed.
References
Important Note
Any medical procedure yielding results outside the norm may be directly or indirectly linked to the conditions outlined on this page. Various factors, including genetics, medication and supplement usage, recent illnesses, pregnancy, pre-test eating, smoking, and stress, can impact the test's outcome. Additionally, factors like false positives, false negatives, inaccurate analyses, and others can influence results.
Reference ranges, which help healthcare professionals interpret medical tests, may vary depending on age, gender, and other factors. They may also differ between laboratories due to variations in instruments and methods used. Optimal ranges are designed for preventive purposes, aiming to identify trends and potential risks early, while normal ranges reflect conventional laboratory values indicating no current disease or pathology. Your healthcare practitioner may have specific reasons for testing that deviate from the usual or may interpret results differently based on individual circumstances. Proper interpretation typically involves considering clinical findings and other diagnostic tests. Hence, it is crucial to provide your healthcare professionals with a comprehensive medical history, consult with them for result interpretation, and follow their guidance for potential re-testing or additional diagnostics.
Disclaimer
This content is provided solely for informative and educational purposes. It is not intended as a substitute for medical advice or treatment from a personal physician. Regarding the interpretation of their medical test results and/or specific health questions, it is recommended that all readers and viewers consult their physicians or other qualified health professionals. The publisher is not responsible for any adverse health effects that may result from reading or following the information in this educational content. Before beginning any nutrition, supplement, or lifestyle program, all viewers, especially those taking prescription or over-the-counter medications, should consult their physician or health care practitioner.
Please note that while prominent lab names are included in this content, we cannot guarantee that these labs offer all the tests mentioned. For confirmation, individuals should contact the labs directly or consult their medical practitioners. The information provided reflects general knowledge at the time of publication and may not include recent updates or emerging research. Readers should verify details with qualified professionals to ensure the most up-to-date and accurate guidance.
[1] Surks MI, Chopra IJ, Mariash CN, et al. American Thyroid Association guidelines for use of laboratory tests in thyroid disorders. JAMA. 1990;263(11):1529-1532.
[2] Klee GG. Clinical usage recommendations and analytic performance goals for total and free triiodothyronine measurements. Clin Chem. 1996;42(1):155-159.
[3] Spencer CA, Hollowell JG, Kazarosyan M, Braverman LE. National Health and Nutrition Examination Survey III thyroid-stimulating hormone (TSH)–thyroxine (T4)–thyroid hormone correlation study. J Clin Endocrinol Metab. 2007;92(12):4575-4582.
[4] Bahn RS, Burch HB, Cooper DS, et al. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Thyroid. 2011;21(6):593-646.
[5] Brent GA. Mechanisms of thyroid hormone action. J Clin Invest. 2012;122(9):3035-3043.
[6] Canaris GJ, Manowitz NR, Mayor G, Ridgway EC. The Colorado thyroid disease prevalence study. Arch Intern Med. 2000;160(4):526-534.
[7] Larsen PR, Davies TF, Schlumberger MJ, Hay ID. Thyroid physiology and diagnostic evaluation of patients with thyroid disorders. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016,12.
[8] Franklyn JA, Boelaert K. Thyrotoxicosis. Lancet. 2012;379(9821):1155-1166.
[9] Bianco AC, Salvatore D, Gereben B, et al. Biochemistry, cellular and molecular biology, and physiological roles of the iodothyronine selenodeiodinases. Endocr Rev. 2002;23(1):38-89.
[10] Brent GA, Larsen PR. The molecular basis of thyroid hormone action. N Engl J Med. 1991;331(13):847-853.
[11] Roti E, Minelli R, Salvi M. Thyroid hormone metabolism and regulation. Endocrinol Metab Clin North Am. 2002;31(1):159-184.
[12] Robbins J. Thyroid hormone transport proteins and uptake mechanisms. Clin Endocrinol (Oxf). 2000;52(4):441-455.
[13] Wartofsky L, Dickey RA. The evidence for a narrower thyrotropin reference range is compelling. J Clin Endocrinol Metab. 2005;90(9):5483-5488.