Thyroid function test in patient with acute-severe-nonthyroidal illnesses.

Patients with acute-severe-nonthyroidal illnesses had FT4 and T3 values below the normal range with the magnitude of change greater for T3 than FT4. Some patients had depressed and some had elevated TSH values. In the recovery phase, FT4 levels appeared to rise before T3 levels and TSH exhibited an exaggerated increase. These results are consistent with other studies which suggest that dysfunction of the hypothalamic-pituitary-thyroid axis may be associated with anomalous results for thyroid function test parameters in patients with acute-severe-nonthyroidal illnesses. This anomaly should be given due consideration when interpreting results of thyroid function test parameters in such patients.