Function tests

Metoclopramide test or Paspertin® Test

• Slight increase of prolactin (15-30 µg/l). The PRL stimulation test can secure the diagnosis of hyperprolactinemia.
• Suspicion of latent hyperprolactinemia (nightly prolactin increase with normal day values), which may lead to follicle maturation disorder, luteal insufficiency or anovulatory cycles.

Metoclopramide test or Paspertin® Test

Metoclopramide (MCP) leads to Dopamine (natural inhibitor of prolactin secretion) inhibition in the hypothalamus and consequent increase of prolactin levels in the blood.

TRH test

As an alternative to MCP stimulation, a TRH test can be carried out. Instead of 10 mg Metoclopramide slow i.v. injection of 200 µg TRH (i.e. Antepan®, Thyroliberin TRH Merck®, TRH Berlin Chemie®, TRH Ferring®). Before and 30 min after TRH administration the prolactin levels are measured.

Prolactin

2ml serum each, before and after MCP-injection.

The test should either be carried out in the early follicle phase or in the middle luteal phase (19^th – 24^th day of cycle). Fasting patient.

1. Initial blood collection prior to MCP-injection.
2. v. injection of 10 mg Metoclopramide (MCP, Paspertin®)
3. Second blood sample to be taken 30 min after MCP-injection.

Side effects:

Occasional nausea, tiredness, unfitness to drive due to this!

MCP stimulation test:

Results of the MCP stimulation test should be interpreted by considering the cycle phase.

Normal values:

Increase of prolactin to 100-200 µg/l. During the follicle phase, the prolactin level should not exceed 230 µg/l and it should not exceed 300 µg/l in der luteal phase.

Latent hyperprolactinemia:

Normal basal value, excessive increase of stimulated prolactin levels to more than 230 µg/l (follicle phase) or 300 µg/l (luteal phase).

Manifested hyperprolactinemia:

Slightly elevated basal value and normal or excessive increase of prolactin of more than 230 µg/l (follicle phase) or 300 µg/l (luteal phase). A raised basal prolactin value, without increase following MCP administration, may point to prolactinoma.

TRH test:

Normal value:

Increase by twice to five times the amount. The increase of prolactin after TRH administration is generally much lower than after MCP administration.

Prolactinoma:

Elevated basal value and missing increase of prolactin in most patients with prolactinoma. In case of latent hyperprolactinemia, the values will rise to up to 40-45 µg/l.