Chapter 6b
Clinical Strategies in the Testing of Thyroid Function

	WHO SHOULD BE TESTED FOR THYROID DYSFUNCTION ?
	The basis for a case-finding strategy
	Sensitivity and accuracy of clinical assessment
	Prevalence
	Adverse consequences of thyroid dysfunction
	Effectiveness of laboratory assays for case finding and screening
	Potential adverse effects of testing
	Safety and effectiveness of treatment
	Follow up of abnormal results
	INTERPRETATION OF TEST RESULTS
	The TSH-free T4 relationship
	Serum free T4-TSH setpoint
	The TSH-T4 relationship: diagnostic assumptions
	APPLICATION AND INTERPRETATION OF INDIVIDUAL SERUM ASSAYS
	TSH as the initial test of thyroid function
	Serum free and total T4
	Indications for measurement of serum T3
	Indications for TRH Testing
	Thyroglobulin
	Thyroglobulin antibody
	Thyroid peroxidase antibody
	TSH receptor antibody
	TSH alpha subunit
	Serum reverse T3
	THYROID TESTING STRATEGIES IN SPECIAL SITUATIONS
	Thyrotoxicosis
	Hypothyroidism
	Assessment of thyroid function during non-thyroidal illness
	Differentiated thyroid cancer
	Psychiatric illness
	Pregnancy
	EUTHYROID HYPERTHYROXINEMIA AND HYPOTHYROXINEMIA
	Euthyroid hyperthyroxinemia
	Euthyroid hypothyroxinemia
	THE PHYSICIAN-LABORATORY INTERFACE
	Historical
	Diagnostic approach to discordant or anomalous assay results
	Clinical feedback, quality assurance and cost effectiveness