Original Title: Dosage sanguin de l’acide valproïque libre par méthode immunologique

Authors' objectives: A request to include a new test to the Répertoire québécois et système de mesure des procédures de biologie médicale (hereinafter the “Répertoire”) was submitted to the Ministère de la Santé et des Services sociaux (MSSS) by the grappe Montréal – Centre hospitalier universitaire de Montréal (CHUM). The MSSS asked the Institut national d’excellence en santé et en services sociaux (INESSS) to assess the advisability of including free blood valproic acid immunoassay in the Répertoire. This is INESSS’s second assessment of this test. The first one, which was carried out in 2014, concluded with a recommendation not to include the test because of a lack of data supporting its clinical validity and utility.

Authors' results and conclusions: RESULTS (#1 POPULATIONAL DIMENSION): In certain clinical situations, the result of a total blood valproic acid assay may not accurately reflect the free fraction of the drug. An underestimation of the free fraction of valproic acid can increase the risk of neurological and hematological toxicities. (#2 CLINICAL DIMENSION): In individuals hospitalized in intensive care with hypoalbuminemia and a neurological toxicity, the free valproic acid level was approximately twice as high as in those without such toxicity. (#3 SOCIOCULTURAL DIMENSION): No clinical practice guideline or health technology assessment report specifically mentioning the relevance of measuring the free blood valproic acid level was found during the review of the scientific and grey literature. (#4 ORGANIZATIONAL DIMENSION): The clinicians consulted consider that immunological methods are suitable for measuring the free fraction of valproic acid in blood. (#5 ECONOMIC DIMENSION): Including this test in the Répertoire would result in costs of $189,537 over the first 3 years for a total of 7,398 tests.

Authors' recommendations: The Institut national d’excellence en santé et en services sociaux (INESSS) recommends that the Minister include free blood valproic acid immunoassay in the Répertoire québécois et système de mesure des procédures de biologie médicale: Monitor the number of requests and the costs associated with the test, and adjust the strategies or interventions used as needed.

Project Status: Completed

Year Published: 2026

URL for published report: https://www.inesss.qc.ca/publications/repertoire-des-publications/publication/dosage-sanguin-de-lacide-valproique-libre-par-methode-immunologique.html

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: Canada

Province: Quebec

Organisation Name: Institut national d'excellence en sante et en services sociaux

Contact Address: L'Institut national d'excellence en sante et en services sociaux (INESSS) , 2021, avenue Union, bureau 10.083, Montreal, Quebec, Canada, H3A 2S9;Tel: 1+514-873-2563, Fax: 1+514-873-1369

Contact Name: demande@inesss.qc.ca

Contact Email: demande@inesss.qc.ca

Copyright: L'Institut national d'excellence en sante et en services sociaux (INESSS)