Table 6.3-3. Tests for pituitary hormone excess or deficiency

Pituitary hormone overproduction (usually if clinically suspected)

Test of choice

Prolactinoma

Serum prolactin measurement (in all)

Cushing syndrome

1-mg dexamethasone suppression test or late-night salivary cortisol test, or 24-h urinary free cortisol test

Acromegaly

Serum IGF-1 level

Thyrotropinoma

FT4, FT3, TSH

Pituitary hormone deficiency

Test of choice

Adrenal insufficiency

Early morning serum cortisol with ACTH measurement +/- ACTH stimulation test

Hypothyroidism

Serum TSH and FT4 measurement (FT4 measurement is the best test for central hypothyroidism)

Hypogonadism

Men: Early morning testosterone measurement with LH measurement

Women: Presence of menstrual periods in premenopausal women. In case of oligomenorrhea or amenorrhea: estradiol and FSH measurement

Central diabetes insipidus

Serum sodium measurement, serum and urine osmolality, water deprivation test if needed (in masses >1 cm and if symptoms are present)

ACTH, adrenocorticotropic hormone; FSH, follicle-stimulating hormone; FT3, free triiodothyronine; FT4, free thyroxine; IGF-1, insulin-like growth factor 1; TSH, thyroid-stimulating hormone.