What It Is
A valproic acid test measures the amount of valproic acid, which is an anticonvulsant
medicine, in a blood sample. Valproic acid is prescribed primarily to prevent
seizures.
The seizure disorder epilepsy is a nervous system condition that causes electrical
signals in the brain to misfire. These disruptions lead to temporary communication
problems between nerve cells, resulting in symptoms that range from mild (blinking
or staring into space) to severe (losing consciousness or whole body shaking).
Seizures may be caused by many different conditions, including infections such
as meningitis or encephalitis; a congenital (present from birth) brain or blood vessel
malformation; brain trauma due to an accident or lack of oxygen at birth; a metabolic
or genetic disorder; brain tumor; or stroke. Frequently, the cause is unknown.
Valproic acid also may be used to treat bipolar disorder, a condition characterized
by periods of intensely high and low moods, or to help prevent migraine headaches.
In many cases, it's used in conjunction with other medications for maximum effectiveness.
Why It's Done
Valproic acid blood levels must stay within a specific range for the drug to work
properly. Doctors must prescribe enough to prevent symptoms, but not so much so as
to cause unwanted side effects. One of the most serious side effects of valproic acid
is liver damage. Because the rate at which the liver can process the drug varies from
person to person, the test is often performed at regular intervals throughout treatment.
If a current dose of valproic acid seems to be working, regular blood tests can
help ensure that the dose remains steady. If symptoms don't seem to be diminishing
or a child is experiencing side effects, the test can be used to adjust the medication
to a more effective dose. This kind of close monitoring is especially important if
other medications are added to the treatment plan, since some can change the way the
body processes valproic acid.
Preparation
No special preparations are needed for this test. Your doctor may recommend that
the test be performed at a certain time — for example, just before your child's
daily dose — since valproic acid levels may fluctuate throughout the day. Also,
it's important to let the doctor know about any other medications your child may be
taking, as these can affect the results.
On the day of the test, it may help to have your child wear a short-sleeve shirt
to allow easier access for the technician who will be drawing the blood.