What test can accurately detect high prolactin levels?

Hyperprolactinemia is a very common disease in women, which can lead to infertility, oligomenorrhea, amenorrhea and other symptoms, causing a lot of trouble to the normal life and psychology of patients. Next, let's take a look at what tests can accurately detect hyperprolactinemia.

1. Determination of reproductive hormones of hypothalamus-pituitary-ovarian axis: FSH and LH decrease, LH/FSH ratio increases. If PRL ≤ 100 ng/ml, it is mostly functional increase, and PRL ≥ 100 ng/ml is mostly tumor increase. The larger the tumor, the higher the PRL. For example, if the tumor diameter is ≤ 5 mm, PRL is (171 ± 38) ng/ml; if the tumor diameter is 5-10 mm, PRL is (206 ± 29) ng/ml; if the tumor diameter is ≥ 10 mm, PRL is mostly (485 ± 158) ng/ml. Plasma PRL may not increase when giant adenoma is hemorrhagic and necrotic.

2. Thyroid, adrenal and pancreatic function tests: When hyperprolactinemia is combined with hypothyroidism, TSH is elevated, and T3, T4, and PBI are decreased. When hyperprolactinemia is combined with Cushing's disease and virilization symptoms, testosterone (T), androstenedione (△4dione), dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), 17-ketosteroids (17KS) and plasma cortisol are elevated. When hyperprolactinemia is combined with diabetes and acromegaly, plasma insulin, blood glucose, and glucagon should be measured and a glucose tolerance test should be performed.

3. Prolactin stimulation test

(1) Thyrotropin-releasing hormone (TRH) test: In normal women, a single intravenous injection of TRH 100-400 pg is given. Within 15-30 minutes, PRL increases 5-10 times compared to before injection, and TSH increases 2 times. There is no increase in patients with pituitary tumors.

(2) Chlorpromazine test: Chlorpromazine inhibits norepinephrine reabsorption and dopamine function through receptor mechanism, thereby promoting PRL secretion. In normal women, after intramuscular injection of 25-50 mg of chlorpromazine, blood PRL increases by 1-2 times compared with before injection within 60-90 minutes and lasts for 3 hours. It does not increase in patients with pituitary tumors.

(3) Metoclopramide test: Metoclopramide promotes the production and release of PRL. In normal women, 30 to 60 minutes after intravenous injection of 10 mg, PRL increased by more than 3 times compared with before injection, but did not increase in patients with pituitary tumors.