Shine B, et al. - Via a Markov model simulation, researchers investigated if measuring free thyroxine (FT4) in addition to thyrotropin (thyroid-stimulating hormone) on all requests for thyroid function tests from primary care on adult patients was cost-effective. For this approach, the incremental cost-effectiveness ratio (ICER) was £71,437. The utilities of the treated hypopituitary state, the probability of going to a general practitioner (GP), and of the GP identifying a hypopituitary patient were factors with a large impact on the ICER. At a cost to the user of an FT4 measurement of £0.61, the ICER would be below £20,000. Routine inclusion of FT4 in a thyroid hormone profile was not considered cost-effective with FT4 measurements at their present cost to the user.