Inappropriate requests for serum anti-epileptic drug levels in hospital practice.
BACKGROUND
Serum anti-epileptic drug (AED) levels are indicated to assess AED adherence or toxicity, and are applicable to only a few AEDs. Expert consensus views on the clinical role of serum AED levels are summarized in the evidence-based guidelines published by the Scottish Intercollegiate Guidelines Network.


OBJECTIVE
To examine local compliance with these guidelines.


METHODS
Retrospective case-note audit.


METHODS
We included all serum AED level measurements requested from our hospital over two months. Our audit standards were first, that serum AED levels should be requested only for suspicion of poor AED adherence or toxicity ('indication-compliant'), and secondly, for 'full compliance', that 'indication-compliant' requests should be made only for AEDs with established dose-response and dose-toxicity relationships (phenytoin, carbamazepine, phenobarbitone).


RESULTS
There were 114 measurements in 102 patients. Serum AED level requests were for phenytoin (n = 50), valproate (n = 27), carbamazepine (n = 22), lamotrigine (n = 8), phenobarbitone (n = 7), and were made by physicians (n = 46), paediatricians (n = 30), neurologists (n = 15), neurosurgeons (n = 14), psychiatrists (n = 7), and intensivists (n = 2). AED toxicity was queried in 29 requests (25%), and adherence in 10 (9%); thus 34% of requests were 'indication-compliant'. However, 16 of these were for valproate or lamotrigine; thus only 23 requests (20%) were 'fully compliant'. Clinical management changed in only 17 of the 47 patients whose levels fell outside target ranges, and only two of these followed indication-compliant AED measurement.


CONCLUSIONS
The audit identified a failure locally to comply with standard evidence-based guidelines. If, as is likely, this reflects practice elsewhere in the UK, there are potentially major clinical management and resource implications.
Walters
R J L
RJ
Epilepsy Unit, Department of Neurology, University Hospital of Wales, Cardiff, UK.
Hutchings
A D
AD
Smith
D F
DF
Smith
P E M
PE
D000927:Anticonvulsants / Q000009:adverse effects / Q000097:blood*; D002983:Clinical Competence; D016903:Drug Monitoring / Q000706:statistics & numerical data*; D019983:Guideline Adherence; D006801:Humans; D008485:Medical Audit / Q000379:methods*; D008505:Medical Staff, Hospital; D010349:Patient Compliance; D012189:Retrospective Studies
D000927:Anticonvulsants