以游離態發爾波克檢測提供癲癇病患血中濃度監控的精準檢驗

Precisely Monitoring Free Valproic Acid Level in Patient with Epilepsy

發爾波克是廣效性的抗癲癇藥物，血中藥物濃度監測大多是定量血中總合發爾波克濃度。總合發爾波克的檢驗方法是以血漿或血清檢體直接使用Dimension ExL機台之同質粒子強化比濁抑制免疫分析法（PETINIA）測量，若要測游離態的檢體需先以10K孔徑的濃縮管經過高速離心，除去與蛋白質結合之藥物後才進行檢測，本研究目的在評估游離態發爾波克的臨床應用。利用病歷回溯分析規則服用發爾波克藥物且同時執行總合及游離發爾波克檢驗的結果，共收集224件報告，以總合發爾波克有效治療濃度範圍為標準分成三個族群，在總合發爾波克濃度未達有效範圍的66筆結果中，有32筆（48%）游離態法爾波克濃度是在有效治療濃度內，8筆（12%）病患超出有效治療濃度，若無游離態法爾波克檢驗，醫師可能會根據總合發爾波克濃度的結果，將這8位病患的藥物劑量再調高，導致藥物對病患產生毒性，這不一致性與病患白蛋白偏低的個案比例有高相關（17/20; 85%）。在另兩個族群也有相同發現。本研究結果顯示，提供游離態法爾波克檢驗，可提高服用此藥物病人血中藥物濃度監測之精確度，讓臨床醫師更準確掌握血中藥物的有效治療濃度及早修正臨床決策。 Valproic acid is a broad-spectrum anti-epileptic drug. Therapeutic drug monitoring of valproic acid is usually by measuring total valproic acid concentrations. Total valproic acid in blood can be directly measured by particle-enhanced turbidity inhibition immunoassay (PETINIA) using the Dimension ExL machine. To measure the free sample, the sample should be treated to remove the protein-bound drug before it is tested. The purpose of this study is to evaluate the clinical application of free-form valproic acid in blood. A total of 224 reports with total and free blood valproic acid concentrations were collected and analyzed retrospectively. Based on the therapeutic range of total valproic acid in blood, the patients were divided into three groups. Of the 66 results in which the valproic acid concentration did not reach the effective range, 32 (48%) of the patients were with free valproic acid within the effective treatment concentration, and 8 (12%) patients with free valproic acid exceeded the effective treatment concentration. If there is no free valproic acid concentration available, the physician may increase the dose for these 8 patients according to the result of the total valproic acid, resulting in toxicity of the drug to the patient. This inconsistency of total and free from of valproic acid was found to be associated with patients with low albumin levels (17/20; 85%). The similar findings were observed in the other two groups. The results of this study show that the free valproic acid test can provide useful information for patients taking this drug and help clinicians to provide best treatment strategy.