Are thyroid function tests too frequently and inappropriately requested?

Elio Roti, E. Gardini, M. G. Magotti, S. Pilla, R. Minelli, M. Salvi, C. Monica, D. Maestri, S. Cencetti, L. E. Braverman

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

In spite of data supporting the use of the serum thyrotropin (TSH) concentration as the best test to detect abnormal thyroid function, measurement of circulating thyroid hormones with or without a serum TSH continues to be frequently requested to evaluate thyroid function. We have analyzed how combinations of thyroid function tests were ordered by referring physicians and the results of the tests in order to offer some suggestions as to how to use thyroid function tests in a cost effective manner. During 1995, 19,181 inpatient and outpatient requests (45,865 different tests) for thyroid function tests were received by the laboratory of a 1600 bed University Hospital in Parma, Italy. The following tests were carried out: T4, free T4, T3, free T3 and TSH. Serum TSH values below and above the normal range were considered to reflect abnormal thyroid function i.e. hyperthyroidism, or hypothyroidism including subclinical disease independent of the results of the other tests. Combinations of ordered tests and the percent of the total for each combination were: TSH+T4+T3 (56%), TSH+FF4+FT3 (14%), TSH (12%), TSH+FT4 (9%), TSH+T4 (1%), TSH+T4+T3+FT4+FT3 (5%), others (3%). The T4+T3+TSH panel (10,780 requests) had normal serum TSH values in 80.6% and the FT4+FT3+TSH panel (2590 requests) had normal TSH values in 73.2%. Elevated serum TSH concentrations were observed more frequently in hospitalized than in ambulatory patients (9.7% vs 7.4% p <0.001). T3 (elevated serum T3, normal T4 and low TSH concentrations) and T4 (elevated serum T4, normal T3 and low TSH concentrations) toxicosis were observed in 8.1% and 9.4%, respectively, of the requested test (NS). FT3 and FT4 toxicosis, defined as for T3 and T4 toxicosis, were observed in 7.5% and 4.9%, respectively (NS). The low T3 and low FT3 syndrome in hospitalized patients was present in 1.6% and 2.3% of the requests, respectively (NS). The low T4+low T3 and low FT4+low FT3 syndrome was present in only 0.3% and 0.2%, respectively, of the requests. Our study shows that a) in hospitalized patients thyroid function tests were requested in 20% of the patients and only one in 14 of these patients at the highest could have abnormal thyroid function, as indicated by abnormal TSH value b) FT4 (or T4) is as useful as FT3 (or T3) in the diagnosis of hyperthyroidism, c) in hospitalized patients the low T3 syndrome was far less common than that reported in the literature, probably due to the lower severity of illness, d) panels which include T3 and FT3 are not justified, and e) serum TSH alone is the most appropriate initial thyroid function test.

Original languageEnglish
Pages (from-to)184-190
Number of pages7
JournalJournal of Endocrinological Investigation
Volume22
Issue number3
Publication statusPublished - 1999

Fingerprint

Thyroid Function Tests
Serum
Thyroid Gland
Euthyroid Sick Syndromes
Hyperthyroidism
Reference Values
Thyrotropin
Hypothyroidism
Thyroid Hormones
Italy
Inpatients
Outpatients
Physicians
Costs and Cost Analysis

Keywords

  • Combinations
  • Number
  • Results
  • Thyroid function tests

ASJC Scopus subject areas

  • Endocrinology

Cite this

Roti, E., Gardini, E., Magotti, M. G., Pilla, S., Minelli, R., Salvi, M., ... Braverman, L. E. (1999). Are thyroid function tests too frequently and inappropriately requested? Journal of Endocrinological Investigation, 22(3), 184-190.

Are thyroid function tests too frequently and inappropriately requested? / Roti, Elio; Gardini, E.; Magotti, M. G.; Pilla, S.; Minelli, R.; Salvi, M.; Monica, C.; Maestri, D.; Cencetti, S.; Braverman, L. E.

In: Journal of Endocrinological Investigation, Vol. 22, No. 3, 1999, p. 184-190.

Research output: Contribution to journalArticle

Roti, E, Gardini, E, Magotti, MG, Pilla, S, Minelli, R, Salvi, M, Monica, C, Maestri, D, Cencetti, S & Braverman, LE 1999, 'Are thyroid function tests too frequently and inappropriately requested?', Journal of Endocrinological Investigation, vol. 22, no. 3, pp. 184-190.
Roti, Elio ; Gardini, E. ; Magotti, M. G. ; Pilla, S. ; Minelli, R. ; Salvi, M. ; Monica, C. ; Maestri, D. ; Cencetti, S. ; Braverman, L. E. / Are thyroid function tests too frequently and inappropriately requested?. In: Journal of Endocrinological Investigation. 1999 ; Vol. 22, No. 3. pp. 184-190.
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AU - Roti, Elio

AU - Gardini, E.

AU - Magotti, M. G.

AU - Pilla, S.

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AU - Salvi, M.

AU - Monica, C.

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N2 - In spite of data supporting the use of the serum thyrotropin (TSH) concentration as the best test to detect abnormal thyroid function, measurement of circulating thyroid hormones with or without a serum TSH continues to be frequently requested to evaluate thyroid function. We have analyzed how combinations of thyroid function tests were ordered by referring physicians and the results of the tests in order to offer some suggestions as to how to use thyroid function tests in a cost effective manner. During 1995, 19,181 inpatient and outpatient requests (45,865 different tests) for thyroid function tests were received by the laboratory of a 1600 bed University Hospital in Parma, Italy. The following tests were carried out: T4, free T4, T3, free T3 and TSH. Serum TSH values below and above the normal range were considered to reflect abnormal thyroid function i.e. hyperthyroidism, or hypothyroidism including subclinical disease independent of the results of the other tests. Combinations of ordered tests and the percent of the total for each combination were: TSH+T4+T3 (56%), TSH+FF4+FT3 (14%), TSH (12%), TSH+FT4 (9%), TSH+T4 (1%), TSH+T4+T3+FT4+FT3 (5%), others (3%). The T4+T3+TSH panel (10,780 requests) had normal serum TSH values in 80.6% and the FT4+FT3+TSH panel (2590 requests) had normal TSH values in 73.2%. Elevated serum TSH concentrations were observed more frequently in hospitalized than in ambulatory patients (9.7% vs 7.4% p <0.001). T3 (elevated serum T3, normal T4 and low TSH concentrations) and T4 (elevated serum T4, normal T3 and low TSH concentrations) toxicosis were observed in 8.1% and 9.4%, respectively, of the requested test (NS). FT3 and FT4 toxicosis, defined as for T3 and T4 toxicosis, were observed in 7.5% and 4.9%, respectively (NS). The low T3 and low FT3 syndrome in hospitalized patients was present in 1.6% and 2.3% of the requests, respectively (NS). The low T4+low T3 and low FT4+low FT3 syndrome was present in only 0.3% and 0.2%, respectively, of the requests. Our study shows that a) in hospitalized patients thyroid function tests were requested in 20% of the patients and only one in 14 of these patients at the highest could have abnormal thyroid function, as indicated by abnormal TSH value b) FT4 (or T4) is as useful as FT3 (or T3) in the diagnosis of hyperthyroidism, c) in hospitalized patients the low T3 syndrome was far less common than that reported in the literature, probably due to the lower severity of illness, d) panels which include T3 and FT3 are not justified, and e) serum TSH alone is the most appropriate initial thyroid function test.

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