Analysis of Free Valproic Acid levels may be useful in delineating the cause of toxicity when the total concentration is not excessive. Geriatric patients often exhibit hypoalbuminemia, which results in a marked decrease in protein-binding sites for drugs. The clinical symptoms of drug intoxication may not be apparent, but may manifest themselves in impaired cognitive function and confusion. Therefore, it is important to evaluate both total and free concentrations
Patient Preparation: Avoid contact of samples with plasticizers, varnishes, paint fumes, and fatty acids. Collect as a trough just before next dose (Optimum time to collect sample: 1 hour before next dose
1.0 mL Serum from a Red Top Tube in a Plastic Vial
7 days Refrigerated
30 days Frozen
Specimen should be drawn 30 minutes prior to next dose
Centrifuge and immediately separate serum or plasma specimens from the cells
0.5 mL
4.8 - 17.3 mg/L
Analysis of Free Valproic Acid levels may be useful in delineating the cause of toxicity when the total concentration is not excessive. Geriatric patients often exhibit hypoalbuminemia, which results in a marked decrease in protein-binding sites for drugs. The clinical symptoms of drug intoxication may not be apparent, but may manifest themselves in impaired cognitive function and confusion. Therefore, it is important to evaluate both total and free concentrations
2 to 3 days
00910164
80165