Comprehensive Thyroid Assessment

The Comprehensive Thyroid Assessment provides a thorough analysis of thyroid hormone metabolism, including central thyroid gland regulation and activity, thyroid hormone production and secretion, peripheral thyroid conversion, and thyroid autoimmunity.

What is the Comprehensive Thyroid Assessment by Genova Diagnostics?

The Comprehensive Thyroid Assessment by Genova Diagnostics is a serum test that includes the following hormones and biomarkers:

Thyroid-Stimulating Hormone (TSH): TSH is a hormone produced by the pituitary gland and regulates thyroid hormone production. Elevated or suppressed levels can indicate thyroid dysfunction and help diagnose hypothyroidism or hyperthyroidism.  [9.]

Free Thyroxine (fT4): fT4 is the precursor to fT3 and serves as an important indicator of thyroid gland function. It helps assess thyroid hormone production and informs thyroid hormone conversion in the body.  [11.]

Free Triiodothyronine (fT3): fT3 is the active form of thyroid hormone and plays a crucial role in regulating metabolism, energy production, and overall cellular function.  [11.]

Reverse T3 (rT3): rT3 is the third most abundant iodothyronine in human blood. It is considered inactive as it weakly binds to thyroid nuclear hormone receptors, potentially hindering T3 production from T4. Elevated serum rT3 levels are associated with non-thyroidal illness syndrome and certain medications like amiodarone, which inhibit rT3 metabolism. Genetic conditions affecting iodothyronine deiodinases, thyroid transporters, and transport proteins can also influence serum rT3 concentration. [3.]

Anti-Thyroglobulin Antibodies (anti-TG): TgAb serves as a marker for Hashimoto’s thyroiditis (HT). It was the initial antibody identified in autoimmune thyroid disease (AITD) by Doniach and Roitt in 1956. Most TgAbs are of the IgG class, though some are IgA. These antibodies can bind to immune cells and antigens within thyroid follicles, potentially leading to tissue damage. Thyroid gland destruction prompts structural alterations in thyroglobulin (Tg), stimulating Tg antibody production. Autoreactive T-cells primarily recognize Tg epitopes that have been iodinated, so increases in iodine concentration may stimulate an autoimmune thyroid response via anti-TG antibodies.  [5.]

Anti-Thyroid Peroxidase Antibodies (anti-TPO): These antibodies target thyroid peroxidase, an enzyme involved in thyroid hormone production. Elevated levels suggest autoimmune thyroid diseases like Hashimoto's thyroiditis.  [7.]

What is the Clinical Relevance of the Comprehensive Thyroid Assessment by Genova Diagnostics?

Thyroid hormone production is centrally regulated through the hypothalamus-pituitary-thyroid axis. Thyroxine (T4), produced by the thyroid gland, undergoes peripheral conversion primarily in liver, kidney and muscle cells to triiodothyronine (T3) and reverse T3 (rT3). 

While T3 is five times as potent as T4 and active at cell nuclei throughout the body, rT3 is inert. 

Thyroid dysfunction can manifest centrally at the HPT (hypothalamic-pituitary-thyroid) axis, in the thyroid gland itself via autoimmune or other mechanisms, or peripherally due to poor conversion.  

Issues with peripheral conversion (reflected by T3 and rT3 levels) and immune system interference (reflected by anti-thyroglobulin and anti-thyroid peroxidase antibodies) may impact hormone production or action at the cellular level. Therefore, a comprehensive assessment of thyroid function should include evaluation of central regulation, peripheral conversion, and autoimmune involvement.

The Comprehensive Thyroid Assessment by Genova Diagnostics can uncover imbalances that may contribute to thyroid dysfunction at various functional levels, with central or peripheral thyroid hormone regulation.  

Who Could Benefit from the Comprehensive Thyroid Assessment by Genova Diagnostics? 

The Comprehensive Thyroid Assessment by Genova Diagnostics provides valuable insights into thyroid function and autoimmunity, shedding insight into hormone imbalances as well as central vs. peripheral regulation of thyroid hormone.   

This enables personalized management approaches for improved patient outcomes.

The following groups of people may benefit from the Comprehensive Thyroid Assessment by Genova Diagnostics: 

‍Individuals with suspected thyroid dysfunction: The profile helps diagnose thyroid disorders by assessing thyroid hormone levels (TSH, T4, T3) and detecting markers of thyroid autoimmunity (TPO and TG antibodies).  [4., 6.]

Individuals with autoimmune thyroid conditions: Monitoring TPO and TG antibodies helps assess disease activity and guide treatment decisions in conditions like Hashimoto's thyroiditis or Graves' disease.  [6.]

Patients with symptoms of thyroid dysfunction: The profile aids in identifying the underlying cause of symptoms such as fatigue, weight changes, infertility, brain fog, and mood disturbances, which could be attributed to thyroid dysfunction.  [4.]

Individuals with a family history of thyroid disorders: For those with a family history, the profile can provide early detection of thyroid abnormalities and allow for preventive measures to be taken. 

Patients with unexplained infertility or menstrual irregularities: Thyroid dysfunction can affect reproductive health, and the profile helps identify thyroid imbalances that may be contributing to fertility issues or menstrual irregularities. [12.]

Individuals with unexplained fatigue: Thyroid dysfunction, particularly hypothyroidism, is a common cause of fatigue. The profile assesses thyroid hormone levels and thyroid autoimmunity markers, helping identify underlying thyroid dysfunction as a potential cause of fatigue.  [4.]

Individuals experiencing unexplained weight gain: Hypothyroidism can lead to weight gain due to a slowed metabolism. By evaluating thyroid hormone levels, the profile aids in diagnosing hypothyroidism, allowing for appropriate treatment and management to address weight gain.  [11.]

People with suspected hormone imbalances: Thyroid hormones play a crucial role in regulating various hormonal pathways in the body. Imbalances in thyroid function can disrupt other hormone systems, contributing to symptoms such as irregular menstrual cycles, mood disturbances, and libido changes. 

The profile provides insights into thyroid function, guiding further investigation and treatment of hormone imbalances.  [10.]

Individuals with symptoms of metabolic dysfunction: Thyroid hormones influence metabolism, and imbalances can affect metabolic rate and energy expenditure. The profile evaluates thyroid hormone levels and thyroid autoimmunity markers, aiding in the identification of thyroid-related metabolic dysfunction.  [4.]

Collection and Shipping: 

This test requires a blood draw.  Please click here for full collection instructions.  

References:

[1.] Chakravarthy V, Ejaz S. Thyroxine-Binding Globulin Deficiency. [Updated 2023 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK544274/

[2.] Farebrother J, Zimmermann MB, Andersson M. Excess iodine intake: sources, assessment, and effects on thyroid function. Ann N Y Acad Sci. 2019 Jun;1446(1):44-65. doi: 10.1111/nyas.14041. Epub 2019 Mar 20. PMID: 30891786. 

[3.] Halsall DJ, Oddy S. Clinical and laboratory aspects of 3,3',5'-triiodothyronine (reverse T3). Ann Clin Biochem. 2021 Jan;58(1):29-37. doi: 10.1177/0004563220969150. Epub 2020 Nov 4. PMID: 33040575.

[4.] Institute of Medicine (US) Committee on Medicare Coverage of Routine Thyroid Screening; Stone MB, Wallace RB, editors. Medicare Coverage of Routine Screening for Thyroid Dysfunction. Washington (DC): National Academies Press (US); 2003. 2, Pathophysiology and Diagnosis of Thyroid Disease. Available from: https://www.ncbi.nlm.nih.gov/books/NBK221541/

[5.] Jo K, Lim DJ. Clinical implications of anti-thyroglobulin antibody measurement before surgery in thyroid cancer. Korean J Intern Med. 2018 Nov;33(6):1050-1057. doi: 10.3904/kjim.2018.289. Epub 2018 Oct 30. PMID: 30396251; PMCID: PMC6234389. 

[6.] Meletis CD. Iodine. Journal of Evidence-Based Complementary & Alternative Medicine. 2011;16(3):190-194. doi:https://doi.org/10.1177/2156587211414424

[7.] Mincer DL, Jialal I. Hashimoto Thyroiditis. [Updated 2023 Jul 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459262/

[8.] Peeters RP, Visser TJ. Metabolism of Thyroid Hormone. [Updated 2017 Jan 1]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK285545/

[9.] Pirahanchi Y, Toro F, Jialal I. Physiology, Thyroid Stimulating Hormone. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499850/ 

[10.] Saran S, Gupta BS, Philip R, Singh KS, Bende SA, Agroiya P, Agrawal P. Effect of hypothyroidism on female reproductive hormones. Indian J Endocrinol Metab. 2016 Jan-Feb;20(1):108-13. doi: 10.4103/2230-8210.172245. PMID: 26904478; PMCID: PMC4743370.

[11.] Shahid MA, Ashraf MA, Sharma S. Physiology, Thyroid Hormone. [Updated 2023 Jun 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK500006/

[12.] Verma I, Sood R, Juneja S, Kaur S. Prevalence of hypothyroidism in infertile women and evaluation of response of treatment for hypothyroidism on infertility. Int J Appl Basic Med Res. 2012 Jan;2(1):17-9. doi: 10.4103/2229-516X.96795. PMID: 23776802; PMCID: PMC3657979.

[13.] Zimmermann MB, Köhrle J. The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health. Thyroid. 2002 Oct;12(10):867-78. doi: 10.1089/105072502761016494. PMID: 12487769.