From the Guidelines
The optimal prolactin range varies by age and sex, but generally, for non-pregnant women, normal prolactin levels typically range from 4 to 23 ng/mL (or approximately 85-500 mIU/L), while for men, the normal range is slightly lower at 3 to 15 ng/mL (approximately 65-330 mIU/L). When evaluating prolactin levels, it's essential to consider the timing of the blood test, as prolactin levels fluctuate throughout the day, with highest levels during sleep and lowest levels in the afternoon 1. According to recent guidelines, a single prolactin measurement taken at any time of the day is sufficient to assess hyperprolactinaemia, but serial measurements over time may be necessary to exclude the effect of stress and prolactin pulsatility 1. The diagnosis of hyperprolactinaemia requires age-specific and sex-specific prolactin reference ranges and the exclusion of confounding conditions such as hypothyroidism, renal and/or hepatic impairment, and use of medications that cause hyperprolactinaemia 1. In children and adolescents, serum prolactin concentrations vary with age and sex, and diagnostic serum prolactin concentrations are usually above 4,000 mU/l (188 μg/l) in patients with prolactinomas 1. It's crucial to note that prolactin levels outside the normal range may indicate various conditions, such as pituitary tumors, medication effects, hypothyroidism, or kidney disease, and abnormal levels may affect reproductive function 1. If prolactin levels are abnormal, additional testing may be necessary to determine the cause and appropriate treatment, which might include medication like cabergoline, the dopamine agonist of choice for treating prolactinoma 1. Key points to consider when evaluating prolactin levels include:
- Age-specific and sex-specific reference ranges
- Timing of blood tests
- Exclusion of confounding conditions
- Serial measurements to exclude stress and pulsatility effects
- Consideration of underlying conditions that may affect prolactin levels.
From the Research
Optimal Prolactin Range
The optimal prolactin range is not explicitly stated in the provided studies. However, the studies discuss the treatment of hyperprolactinemia and prolactinomas, which can provide insight into the desired prolactin levels.
Prolactin Levels in Hyperprolactinemia Treatment
- The study 2 found that dopamine agonists significantly reduced prolactin levels, with a weighted mean difference of -45 and a 95% confidence interval of -77 to -11.
- The study 3 states that prolactin normalization is achieved in 80-90% of prolactinomas treated with cabergoline.
- The study 4 mentions that any bromocriptine-resistant patient should be switched to cabergoline, which will normalize prolactin in 80% of patients.
Factors Affecting Prolactin Levels
- The study 5 discusses the risk factors for impulse control disorders in hyperprolactinemic patients on dopamine agonist therapy, including younger age, male gender, smoking, and alcohol use.
- The study 6 highlights the role of prolactin in metabolic disease and the effects of dopamine agonists on metabolic profiles.
Treatment Goals
- The primary goal of treatment for hyperprolactinemia and prolactinomas is to reduce prolactin levels to normal range, which can vary depending on the individual and the laboratory conducting the test.
- The study 2 suggests that dopamine agonists are effective in reducing prolactin levels and persistent hyperprolactinemia, with cabergoline being more efficacious than bromocriptine.
- The study 3 discusses the various treatment options for prolactinomas resistant to dopamine agonists, including temozolomide, aromatase inhibitors, and peptide receptor radionuclide therapy.