Prolactin testosterone test is done to fertility issues in males and female. It may be done to diagnose menstrual irregularities and dysfunctions. In women having difficulties conceiving, it is done to diagnose the cause for infertility. Altered LH/FSH ratio may point towards PCOS. In lactating mothers the prolactin levels are assessed to diagnose problems in milk secretion. It is done in males to diagnose reasons for infertility, low sperm count or testicular issues. In children it may be done to diagnose early or delayed puberty based on the levels.

It helps in evaluating the function of reproductive organs in both males and females.

Prolactin testosterone test measures the levels of FSH, LH, Prolactin and Testosterone hormones in the blood.

The level of FSH-LH-Prolactin and Testosterone in blood.  FSH-LH-Prolactin is a hormone produced by the pituitary gland. It is a tiny gland that is found below the brain.

During prolactin testosterone test blood sample is taken from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a  little sting when the needle goes in or out. This usually takes less than five minutes. In new-borns the blood is taken from the skin behind the heel.

An elastic band will be wrapped around the upper arm by a medical expert to exert pressure after the region of skin has been cleaned. You’ll be instructed to make a fist. This allows blood to pass through the vein. The blood is then drawn out of the vein using a needle. The blood is drawn into a syringe or vial. To stop bleeding, the elastic band is unfastened and the area is wrapped with cotton or a bandage. The laboratory receives the blood sample for analysis.

FSH-LH-Prolactin needs to be present in certain levels at specific time of the menstrual cycle for successful conception. Abnormal levels in any of these may lead to PCOS and infertility issues. High FSH-LH levels in women may mean primary ovarian insufficiency, Turners syndrome, ovarian malignancies, or early onset of menopause. High LH/ FSH ratio is seen in polycystic ovarian syndrome (PCOS). 
In men, high FSH-LH may indicate testicular issues, Klinefelter syndrome or low sperm count. All these may indicate infertility in men. 
In children, high levels before puberty, signify early onset puberty. 
High prolactin levels may be seen in PCOS, hypothyroidism and hypogonadism. 
Low levels of FSH-LH may lead to lack of ovulation and sperm production leading to infertility issues in both men and women. Low levels may be due to problems in the hypothalamus or pituitary gland, being underweight or other central nervous system issues. 
In children, low FSH-LH levels may signify delayed puberty. 
High testosterone may occur in uterine fibroids in women and testicular tumours in men. Low levels may lead to lack of ovulation and sperm production leading to infertility issues in both men and women. Low levels may be due to problems in the hypothalamus or pituitary gland, being underweight or other central nervous system issues. In children, low levels may signify delayed puberty. It may be due to Turner’s syndrome in females , Klinefelter’s syndrome in males or some other infections causing sexual issues. Low prolactin levels may also occur due to pseudohypoparathyroidism.