A patient presents after an episode of syncope vs seizure.

 

Can a serum prolactin level be helpful in differentiating the cause?

Answer:  Not really

The level may rise after generalized seizures, but it may also rise after syncope, so it is unhelpful in differentiating between the two.

 

What is it good for?

The test has a good PPV differentiating true seizure from psychogenic seizures, if the test is positive.

However, the sensitivity is poor and it can not exclude epileptic seizures or support a psychogenic diagnosis.

 

How is it done?

A level is drawn 10-20 minutes after the event, another level is drawn 6 hours later and the two are compared.

What amount of rise is significant is not established.  Some centers use x2 the baseline level to be positive.

Source:

Chen DK, So YT, Fisher RS, Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Use of serum prolactin in diagnosing epileptic seizures: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 2005;65(5):668.