Meijboom RW, et al. - This systematic review was conducted to examine the requirement for annual laboratory follow-up of liver enzymes, electrolytes, and full blood count (FBC) in patients treated with valproic acid (VPA). In VPA treatment, long-term monitoring was necessary only when there had been dose adjustments, co-medication switches, or co-morbidity. Annual laboratory follow-up could be discontinued after 2 years of VPA treatment in uncomplicated cases. For the detection of hepatotoxicity, encouraging patients to be vigilant was more effective than laboratory testing. Follow-up of FBC at 3–6 months, 1 year, and 2 years after start or after a dose increase of VPA or interacting medication was sufficient.