A subnormal or reduced concentration of pituitary hormones is diagnostic of hypopituitarism. Patients with complete hormonal deficiencies are mostly symptomatic and have low serum concentrations of both, the pituitary hormones as well as the target-organ hormones. Patients having partial hormonal deficiencies are detected by dynamic tests/stimulatory tests such as corticotropin stimulation, insulin-induced hypoglycemia and metyrapone test. Corticotropin deficiency is detected by assessing basal cortisol secretion. Patients with intermediate cortisol levels need to be tested for adrenocorticotrophic hormone (ACTH) reserve. There are several tests to check the ACTH reserve. Metyrapone test is preferred over others as it is applicable to all adults with no age restriction and has good correlation with stress related cortisol response. Patients with hypopituitarism are screened for hypothyroidism by measuring thyroxine, total thyroxine (T4) and triiodothyronine (T3) uptake, and free T4. Gonadotropin deficiency is confirmed with low estradiol, low testosterone, and low/normal serum FSH/LH. Growth hormone deficiency is confirmed with provocative tests (insulin induced hypoglycemia and arginine and GHRH combination) for growth hormone (GH) secretion resulting in subnormal levels of serum GH levels, serum insulin-like growth factor-1 levels lower than the age-specific lower limit of normal and deficiency of more than one pituitary hormones, such as ACTH, TSH, and gonadotropins. ADH deficiency is assessed by water deprivation test and ADH suppression test. Prolactin deficiency can be confirmed by directly measuring prolactin levels on more than one occasion as its secretion is episodic but it is not done routinely as it is not clinically significant.
Hypopituitarism laboratory findings
Hypopituitarism physical examination
Sheehan's syndrome laboratory findings
Acromegaly laboratory findings
Adrenal atrophy laboratory findings
Thyroid adenoma laboratory findings
Cushing's syndrome laboratory findings
Secondary adrenal insufficiency laboratory findings