Jostel's TSH index

Jostel's TSH index
Medical diagnostics
Reference range 1.3–4.1

Jostel's TSH index (TSHI or JTI), also referred to as Thyroid Function index (TFI) is a method for estimating the thyrotropic (i.e. thyroid stimulating) function of the anterior pituitary lobe in a quantitative way.[1] The equation has been derived from the logarithmic standard model of thyroid homeostasis.[2][3][4][5] As of 2014 further study is required to show if it is useful.[6]

How to determine JTI

Jostel's TSH index can be calculated with

from equilibrium serum concentrations of thyrotropin (TSH), free T4 (FT4) and a correction coefficient derived from the logarithmic standard model (β = 0.1345).

An alternative standardised form (standardised TSH index or sTSHI) is calculated with.[1]

as a z-transformed value incorporating mean (2.7) and standard deviation (0.676) of TSHI in a reference population[4]

Reference ranges

ParameterLower limitUpper limitUnit
TSHI1.3[1]4.1[1]
sTSHI-2[1]2[1]

Clinical significance

The TSH index is reduced in patients with secondary hypothyroidism resulting from thyrotropic insufficiency.[1][7] For this indication, it has, however, up to now only been validated in adults.[8] JTI was also found reduced in cases of TACITUS syndrome (non-thyroidal illness syndrome) as an example of type 1 thyroid allostasis.[9] Conversely, an elevated thyroid function index may serve as a biomarker for type 2 allostasis and contextual stress.[10]

Recent research demonstrated the TSH index to inversely correlate to thyroid's secretory capacity and thyroid volume.[11] It is unclear if this finding reflects shortcomings of the index (i.e. low specificity in the setting of subclinical hypothyroidism) or plastic responses of the pituitary gland to beginning hypothyroidism.

See also

References

  1. 1 2 3 4 5 6 7 Jostel A, Ryder WD, Shalet SM (October 2009). "The use of thyroid function tests in the diagnosis of hypopituitarism: definition und evaluation of the TSH Index". Clin. Endocrinol. (Oxf). 71 (4): 529–34. doi:10.1111/j.1365-2265.2009.03534.x. PMID 19226261.
  2. ↑ Reichlin S, Utiger RD (February 1967). "Regulation of the pituitary-thyroid axis in man: relationship of TSH concentration to concentration of free and total thyroxine in plasma". J Clin Endocrinol Metab. 27 (2): 251–255. doi:10.1210/jcem-27-2-251. PMID 4163614.
  3. ↑ Cohen, J. L., Thyroid-stimulation hormone and its disorders. In: Becker, K. L. (Hrsg.) Principles and Practice of Endocrinology and Metabolism. S. 144–52, J. B. Lippincott Company, Philadelphia, PA, USA, 1990
  4. 1 2 Johannes W. Dietrich, Gabi Landgrafe, Elisavet H. Fotiadou: TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis. In: Journal of Thyroid Research. 2012, 2012, S. 1–29, doi:10.1155/2012/351864. PMID 23365787.
  5. ↑ Dietrich, Johannes W.; Landgrafe-Mende, Gabi; Wiora, Evelin; Chatzitomaris, Apostolos; Klein, Harald H.; Midgley, John E. M.; Hoermann, Rudolf (2016-06-09). "Calculated Parameters of Thyroid Homeostasis: Emerging Tools for Differential Diagnosis and Clinical Research". Frontiers in Endocrinology. 7. doi:10.3389/fendo.2016.00057. PMC 4899439. PMID 27375554.
  6. ↑ Fliers, Eric; Korbonits, Marta; Romijn, J. A. (2014). Clinical Neuroendocrinology. Elsevier. p. 146. ISBN 9780444626127.
  7. ↑ Chiloiro, Sabrina; Tartaglione, Tommaso; Capoluongo, Ettore Domenico; Angelini, Flavia; Arena, Vincenzo; Giampietro, Antonella; Bianchi, Antonio; Zoli, Angelo; Pontecorvi, Alfredo; Colosimo, Cesare; De Marinis, Laura (1 August 2018). "Hypophysitis outcome and factors predicting responsiveness to glucocorticoid therapy: a prospective and double-arm study". The Journal of Clinical Endocrinology & Metabolism. doi:10.1210/jc.2018-01021. PMID 30085134.
  8. ↑ Schoenmakers N, Alatzoglou KS, Chatterjee VK, Dattani MT. Recent advances in central congenital hypothyroidism. J Endocrinol. 2015 Dec;227(3):R51-71. doi:10.1530/JOE-15-0341. PMID 26416826; PMC 4629398.
  9. ↑ Fan, S; Ni, X; Wang, J; Zhang, Y; Tao, S; Chen, M; Li, Y; Li, J (February 2016). "Low Triiodothyronine Syndrome in Patients With Radiation Enteritis: Risk Factors and Clinical Outcomes an Observational Study". Medicine. 95 (6): e2640. doi:10.1097/MD.0000000000002640. PMC 4753882. PMID 26871787.
  10. ↑ Lei MK, Beach SR, Simons RL, Barr AB, Cutrona CE, Philibert RA. Stress, relationship satisfaction, and health among African American women: Genetic moderation of effects. J Fam Psychol. 2016 Mar;30(2):221-32. doi:10.1037/fam0000140. PMID 26376424; PMC 4749476.
  11. ↑ Hoermann, R; Midgley, JEM; Larisch, R; Dietrich, JW (19 July 2018). "The Role of Functional Thyroid Capacity in Pituitary Thyroid Feedback Regulation". European journal of clinical investigation: e13003. doi:10.1111/eci.13003. PMID 30022470.
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