title: [Low levels of TSH measured by a sensitive assay: do they reflect hyperthyroidism? A critical analysis of 580 cases].
abstract: Highly sensitive TSH assays make it easier to diagnose thyroid diseases. During one year, we performed 5,300 sensitive TSH assays (normal range: 0.15-4 mU/l) in various patients. The purpose of this work was to test the value of the low TSH plasma concentrations found in 580 patients. In 99.7 percent of the cases, low TSH levels were the consequence of a thyroid disorder or a treatment by thyroid hormones; non thyroidal illnesses were detected in only 0.3 percent. However, not all TSH values below 0.15 mU/l were associated with overt or occult thyrotoxicosis. When TSH was undetectable (less than 0.04 mU/l), and excluding thyroid hormone-treated patients, thyrotoxicosis was present in 97 percent of the cases. On the other hand, when TSH values were between 0.04 and 0.15 mU/l, 41 percent of the patients failed to show any sign or symptom of hyperthyroidism, although they had functioning thyroid nodules, multinodular goitre or iodine overload, or they received thyroid hormones.
authors: Service de Médecine C, Centre Hospitalier Régional et Universitaire, Angers.
authors: V
authors: V
authors: Rohmer
authors: A
authors: A
authors: Ligeard-Ducoroy
authors: R
authors: R
authors: Perdrisot
authors: V
authors: V
authors: Beldent
authors: P
authors: P
authors: Jallet
authors: J C
authors: JC
authors: Bigorgne
mesh_terms: D006801:Humans; D006980:Hyperthyroidism / Q000175:diagnosis*; D007159:Immunologic Tests; D013959:Thyroid Diseases / Q000175:diagnosis; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood
chemical_list: D013972:Thyrotropin; D013974:Thyroxine
vernacular_title: Les valeurs basses de la TSH mesurée par méthode ultra-sensible sont-elles le témoin d'une hyperthyroidie? Analyse critique de 580 observations.