Primary, subclinical or central
Thyroid response to acute or chronic illness
Consistent with primary hyperthyroidism
Suggestive of subclinical hyperthyroidism if asymptomatic
Nonspecific, with several potential causes including central hypothyroidism
Consistent with primary hypothyroidism
Suggestive of subclinical hypothyroidism if asymptomatic
Nonspecific, with several potential causes including central hyperthyroidism
First line test for thyroid dysfunction
Measure of non-protein bound thyroxine
Rarely used in diagnosis of thyroid disease
Rarely measured in clinical practice
Present in Hashimoto's, though rarely required for diagnosis
Pathognomonic of Grave's, though not always required for diagnosis
