Blood beta-hydroxybutyrate correlates better with seizure reduction due to ketogenic diet than do ketones in the urine

PURPOSE To investigate whether it is better to use blood beta-hydroxybutyrate (BHB) or urinary ketones to monitor ketogenic diet (KD). METHOD In 33 patients on KD we measured ketosis in two different ways. At the 3-monthly visits to the clinic we measured BHB in capillary blood obtained by finger-prick and the level of ketones in the urine using a urine dipstick. If the patient was able to collect urine, the urinary ketones were also measured every day at home. We compared the degree of ketosis with seizure reduction. RESULTS BHB measured during the 3-monthly visits correlated with seizure reduction at 3 and 6 months (p=0.037 and 0.019, respectively). Urinary ketones measured at the same time did not correlate at any visit. The averaged values of the daily measured ketones in the urine did not correlate either. CONCLUSIONS BHB correlates better with seizure reduction than do ketones in urine. It is, therefore, better to use BHB to monitor KD even if BHB is measured less frequently than urinary ketones.