This document outlines a laboratory testing strategy for evaluating thyroid dysfunction and disease. It recommends measuring TSH levels for minimal or no clinical manifestations to screen for hyperthyroidism or hypothyroidism. For overt clinical manifestations, it suggests measuring both TSH and FT4 to confirm hyperthyroidism or hypothyroidism. Subclinical cases can be identified by a normal FT4 but high TSH for hypothyroidism or low TSH for hyperthyroidism.