Serum and plasma for total and free anticonvulsant drug analyses: effects on EMIT assays and ultrafiltration devices.
The suitability of serum and plasma anticoagulated with heparin, EDTA, citrate, or oxalate was assessed for analysis of free and total phenytoin, carbamazepine, and valproic acid. The free fraction was isolated by ultrafiltration through FreeLevel devices (Syva, Palo Alto, CA). Serum, heparin, and EDTA plasma were satisfactory for both free and total phenytoin and carbamazepine. EDTA could not be used for EMIT (Syva) analysis of valproate. Citrate and, to a lesser degree, oxalate cause a significant negative interference in the concentration of these three drugs as measured both by EMIT and gas-liquid chromatography.
D000927:Anticonvulsants / Q000097:blood*; D002220:Carbamazepine / Q000097:blood; D006801:Humans; D007124:Immunoenzyme Techniques; D010672:Phenytoin / Q000097:blood; D010949:Plasma / Q000032:analysis; D014462:Ultrafiltration / Q000379:methods; D014635:Valproic Acid / Q000097:blood
D000927:Anticonvulsants; D002220:Carbamazepine; D014635:Valproic Acid; D010672:Phenytoin