Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Valproate has a different spectrum of anticonvulsant activity to the other commonly used anticonvulsants, and it is the drug of choice for the treatment of myoclonic seizures and generalised absence seizures because of its minimal sedative action and absence of CNS side effects.It is also effective in general and partial epilepsy and has been used in the prophylaxis of febrile convulsions.
Valproate is an effective option in the therapy of bipolar affective disorder.
Specimen container paediatric:
Serum (SST or plain tube)
Specimen container adult:
Serum (SST or plain tube)
Minimum volume paediatric:
0.5 mL
Minimum volume adult:
1 mL
Special requirements:
Trough sample required
Sample stability:
Unseparated sample: 2 days
Separated sample:
2 days at 15 to 25°C,
2 days at 2 to 4°C,
3 months at -20°C
Interpretation:
Monitoring therapy
Pharmacokinetic studies indicate a poor relationship with pharmacodynamics.
Most authorities agree routine monitoring is not necessary
Monitoring is found useful when compliance is an issue
Little hard evidence for a therapeutic valproate range though 50 – 100mg/L is often quoted. It is clear that some patients are well controlled with concentrations well below 50mg/L and others may require well in excess of 100mg/L.
Toxicity
Important side effects include weight gain, paediatric hepatotoxicity and hyperammonaemia. There is also a possible teratogenic effect.
Reference ranges:
Therapeutic Range 50 to 100 mg/L
Other info:
Lithium heparin plasma samples also acceptable