1st order laboratory parameters-obligatory laboratory tests.
- Hormone diagnostics
- Stage I:
- Basal prolactin (in fasting state; for detailed information on prolactin, see laboratory diagnostics) – this should be determined several times!
- Thyroid-stimulating hormone (TSH).
- Stage II:
- Prolactin (PRL) after TRH administration – used to determine the functional reserve of the prolactin-producing cells of the pituitary gland (e.g., in Chiari-Frommel syndrome, Forbes-Albright syndrome, pituitary adenoma, or hyperprolactinemic amenorrhea).
- Prolactin stimulation test with MCP.
- Stage I:
- Pregnancy test (quantitative HCG).
Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification.
- Pituitary function diagnostics (pituitary partial functions by stimulation tests) – if prolactinoma is detected, the other functions of the pituitary gland should be checked! [the following hormones may drop in the presence of a prolactinoma: LH, FSH, TSH, ACTH, testosterone, T3, T4, and cortisol]
- Somatotropic hormone (STH) (synonyms: somatotropin; English somatotropic hormone; HGH or hGH (human growth hormone), GH (growth hormone), growth hormone) – exclusion of an adenoma that simultaneously produces prolactin and STH (acromegaly).
Other indications
- If drug-induced hyperprolactinemia is suspected, the intake/supply of the responsible drug should be interrupted for 3 days, if possible.
- PRL values above 200 ng/ml (= μg/L) are almost always evidential for a prolactinoma (= macroprolactinoma); elevated prolactin levels up to 200 ng/ml may be due to a microadenoma, among other causes.
