Is routine measurement of TSH in hospitalized patients necessary?

Abstract

TSH routine testing in hospitalized patients has low efficacy, but may be beneficial in a selected subgroup of patients. Our aim was to evaluate the efficacy of routine thyroid function tests among patients admitted to internal medicine departments. It is a retrospective study. A randomly selected cohort of hospitalized patients with abnormal thyroid-stimulating hormone (TSH) blood tests drawn as part of admission protocol. Patient data were collected from the electronic medical files and analyzed for its efficacy. TSH as a screening test was proven unnecessary in 75% (174) of the study population. Leading causes were non-thyroidal illness syndrome, drugs affecting the test results and subclinical disorders. TSH testing was found to be clinically helpful in only 9 patients; however, all of them had other clinical need for TSH testing. We found a clinically abnormal TSH in 20 patients, hypothyroidism in 11 patients and thyrotoxicosis in 9 patients. Low efficacy ascribed to TSH screening test by this study correlates with recent recommendations that indicate TSH screening in admitted patients only with accompanying clinical suspicion. Most probably, the majority of patients found by screening to have thyrotoxicosis have non-thyroidal illness or drug effects so the threshold for FT4 to diagnose overt thyrotoxicosis should be higher than that in ambulatory patients. In elderly patients, clinically relevant TSH disturbances are more frequent and are harder to diagnose, therefore, TSH screening in this group of patients might be beneficial.