Request of thyroid function tests from Primary Care in Spain

Abstract

Background and objectives: Laboratory tests are crucial for diagnosis and monitoring of thyroid disorders. It is therefore necessary to study the pattern and variability in requests of thyroid function tests. The study objectives were to compare the inter-regional variability in the request of laboratory thyroid tests by general practitioners (GPs) in Spain, and to investigate the potential economic savings if the goals set for some suitability indicators were reached.

Methods: Test requests per 1,000 inhabitants and test ratios (free thyroxine (FT4)/thyrotropin (TSH), free triiodothyronine (FT3)/TSH, thyroglobulin antibody (TgAb)/peroxidase antibody (TPOAb)) were compared between the different areas, according to their setting, location, and management. The resulting savings if each department achieved the goals for indicator (0.25 for FT4/TSH, 0.1 for FT3/TSH) were estimated.

Results: Seventy-six laboratories covering a population of 17,679,195 inhabitants participated in the study. TSH was requested significantly less in urban-rural areas, and the requests for FT3/1,000 inhabitants, FT3/TSH, and TgAb/TPOAb were higher in departments with private management. The savings generated if specifications for the ratios of related tests were met would be 937,260.5 €.

Conclusions: The high variability reported in requests for thyroid function and autoimmunity tests in Spain suggests the need for implementing strategies to improve use of such tests.

Keywords: Adecuación; Clinical laboratory; Laboratorio; Pruebas de función tiroidea; Suitability; Thyroid function tests; Variabilidad clínica; Variability.