prolactin (prl) Test

Prolactin (PRL) is a hormone produced by the posterior pituitary gland, and its primary function is lactation. Prolactin plays a major role in lactation in women post childbirth. But the role of Prolactin in men is not much. Prolactin plays another major role in male and female sexual satisfaction.

The prolactin test assesses the quantity of prolactin in the blood. It triggers breast development and milk production in women. In males, there is no known normal function of prolactin. Prolactin test results show other problems created by the hormone.

Prolactin quantities in the blood help diagnose:

• The reasons of galactorrhea (milky or clear white discharge from breasts of non-pregnant/lactating women). Galactorrhea is common in women, men and also in infants.

• The reasons for headaches and visual disturbances Ascertain infertility and erectile dysfunction in men.

• Detection of infertility in females To asses and monitor anterior pituitary gland function (along with other hormones)In cases of failed lactation. 

A prolactin test determines prolactin levels in the blood, to detect if prolactin levels are higher than normal, to monitor the progress of pituitary tumours, prolactinoma recurrence and to find the cause of:

• Breast milk production that is not related to childbirth (Galactorrhea)

• Impotence

• Erectile dysfunction

• Infertility

• Irregular menstrual periods

• Prolactin levels are also often ordered in men as a follow-up to a low testosterone level.

Symptoms observed in this case are: 

• Symptoms can be caused by the growth of a tumour and/or by the hormones produced by a tumour

High Prolactin level symptoms may include:

• A headache

• Some loss of vision

• Less frequent or no menstrual periods or menstrual periods with a very light flow. (Scanty/Irregular menses)

• Trouble becoming pregnant or an inability to become pregnant

• Impotence in men

• Lower sex drive

• The flow of breast milk in a woman who is not pregnant or breastfeeding

• Delay in puberty

• Decrease libido in men

• Decrease fertility

• Erectile dysfunction in men

Too little prolactin level results in the following symptoms:

• A headache

• Loss of body hair (seen more routinely along with thyroid dysfunction)

• In women, less frequent or no menstrual periods or no milk from the breasts

• In men, loss of facial hair, the growth of breast tissue, and impotence

• In women and men, lower sex drive

• In children, slowed growth and sexual development

• In patients of PCOD/PCOS

If the prolactin-making cells in your pituitary gland begin to mutate and grow out of control, they can form tumours known as the Prolactinomas. Prolactinomas, also known as lactotroph adenomas, are not cancerous cells. They happen most often in women age less than 50. In cases of Prolactinomas symptoms, two more tests are taken along with the prolactin blood test.

• Brain imaging -Image generated by a magnetic resonance imaging scan of your brain shows a pituitary tumour

• Vision tests -Confirms if sight is impaired by a pituitary tumour

Added further, the doctor refers you to an endocrinologist the one who is an expert in endocrine system to further verify the situation. They are:

• Serum quantitative HCG measurement

• CT of the pituitary fossa

• MRI of head

• MRI of the pituitary fossa

• Plasma FSH measurement

• Video EEG

The age or gender of the person being tested may affect when and how often a lab test is required. A blood sample is collected from the arm vein or umbilical cord.

Venous blood: A vein from the arm is selected. A large rubber strap may be secured above the vein. The skin over the vein will be cleaned, and a needle will be inserted. Blood will be collected into one or more tubes, and the strap will be removed. A cotton piece is given to stop the blood.

Umbilical cord blood: The lab technician uses a needle and syringe to draw blood from the umbilical cord of a newborn, while the cord is still attached to the infant. Blood samples may also be collected from the part of the umbilical cord that has been detached from the infant. The detached umbilical cord stump or its blood vessels from the infant is used temporarily for medical purposes.

Sometimes the test is repeated for a series of results. A lab test is done immediately if an emergency. But the test is delayed if the condition needs to be monitored and cured.

There can be a little amount of risk for complications during the PRL test. After the blood is drawn, the puncture site might get a bit bruised. It is advisable to put some pressure for a few minutes on the puncture site in order to reduce the blood flowing/oozing out. You might get a small bruise at the puncture site after blood is drawn. You might feel lightheaded or faint. Often, in few rarest of the cases, the veins are seen to be inflamed post the test. You may use the hot press remedy to feel relieved. Ideally, if you have a bleeding disorder, then you might face continued bleeding. Also, make it a point to inform your doctor if you have been advised to take blood-thinning medications like warfarin or aspirin.

• Certain psychiatric medicines, oral estrogen drugs, high blood pressure drugs and hypothyroid medicines may cause prolactin levels to be higher than normal. Inform your doctor if you are taking any tablets.

• If you have kidney or liver disease, you may also have high prolactin levels.

• High-Stress Levels

• Sleeping problems

• Heavy exercise before the test can also influence the results

• Avoid alcohol 24 hours before the blood test

• Specimen type 1: Serum (Blood Sample) 

Specimen collection procedure: Venipuncture(Collection of blood from a vein, usually from the arm)

• Specimen type 2: Umbilical cord blood

PRL Test results may vary depending on your age, gender, health history, the method used for the test. Results are given in micrograms per litre (µg/L). A normal blood level of prolactin is less than 20 µg/L. If your PRL test result shows abnormally high prolactin levels, you may need imaging tests to find out whether you have a prolactinoma tumour. Serum prolactin levels of 25-50 ng/mL are known as 'idiopathic hyperprolactinemia'.

Preparatory instructions before the test *:

• The sample should be collected 3 to 4 hours after waking, ideally before noon as prolactin levels are routinely high in the evening due to circadian rhythm.

• No Fasting Required.

• No other special preparations required

• If the blood is to be taken from the umbilical cord of the newborn, the lab technician will explain to you how to get ready and how it will be taken.

You can expect the prolactin test results within 24 to 36 hours.

The prolactin test cost ranges between 300 to 500 rupees depending on the city.

The doctor may request an MRI scan to check if a prolactinoma tumour is a reason for high Prolactin Levels. The doctor will prescribe medication to shrink an existing tumour. Hyperprolactinemia treatment usually gets cured without treatment after several months. If your prolactin levels do not go down, your doctor will likely prescribe medication of 5-10 mg of bromocriptine.

Infertility caused by high prolactin levels can be reversed once prolactin levels return to normal and the chances of getting pregnant are more. If pregnancy happens, inform your doctor or endocrinologist, and you will be asked to stop taking your medication. Prolactinoma and hyperprolactinemia are not life-threatening. Sometimes the doctor makes changes in your medication plans, does frequent monitoring and asks you to take a series of blood test to keep track of the prolactin level changes.