Figure 4.

Congenital hypothyroidism: Diagnostic algorithm. Diagnostic algorithm: the diagnosis of congenital hypothyroidism begins with either abnormal newborn screening test results or a clinical suspicion of hypothyroidism, leading to serum thyroid function tests (typically TSH and free T4) to confirm the diagnosis. If a diagnosis of primary or secondary (central) congenital hypothyroidism is confirmed, other diagnostic studies can be undertaken to determine the underlying etiology.