Abstracts

Rationale: We wanted to analyze the yield of standardized testing protocols for patients on the ketogenic diet (KD) in terms of clinically actionable results, and the actual actions taken. Our current lab testing protocol is based on the consensus statement published in 2008 from ILAE by Kosoff et al.  It  involves 11 laboratory tests every 3 months (Selenium, Phosphorus, Zinc, Magnesium, CMP, CBC, Vitamin D, Carnitine profile, Urinalysis, B-hydroxybutyrate, Urine Ca/Cr Ratio) with the addition of fasting lipids every 6 months. Methods: We selected patients ages 1 year to 18 years who have been on KD  for at least 6 months from January 2003. Using RedCap database, we collected information for up to the first seven KD clinic follow-up visits for each patient starting with visit 1 after diet initiation (DI) . Data collected included date of DI, duration of time on the diet, type of diet :KD vs Modified Atkins diet- (MAD), diet prescription (KD  ratio or grams of carbohydrate per day), type of feeding (oral vs tube fed), and laboratory values for selenium, phosphorus, zinc, magnesium, carnitine profile, B-hydroxybuturate, and bicarbonates available  at each  visit. We also reviewed all clinical documentation for mention of skin, hair, or nail changes, alterations made to diet therapy based on labs, and if the diet provided a 50% reduction in seizures at each visit. We also looked at lab charges for each of these tests per visit. Results: 79 patients were analyzed at onset of which 61 were fed orally and 18 via G tube. 40 patients completed 2 year visits.  75 patients were still on diet at end of study while 4 had completed treatment. 70 were on KD while 9 were on MAD.  Average duration on diet was 47.45 months ( IQR: 18.8-77 mo). Average lab values at each visit are documented in table 1. Proportion of patients with labs  reporting 50% reduction in seizures at visit 1 was (60/79) versus 34/41 at visit 7 .The most common abnormality barring betahydroxybutyrate was in acyl carnitine ( 73.4%) , followed respectively by phosphorus(44.7%); selenium (8.8%); zinc(7.7%), magnesium (6.1%). Rarely did any mineral deficiencies reflect in reported symptoms (hair or skin changes noted a maximum of 5 times in any visit). Changes were most frequently made for abnormal carnitine levels (44%) followed by bicarbonate (37%) and selenium (28%)- table :2. No patients had any life threatening abnormalities Conclusions: After reviewing costs of laboratory testing for families (tests ranging from $88.78- $224.70) and the relative infrequent management changes based on zinc, phosphorus and magnesium abnormalities, it may not be necessary to test the entire set of laboratory measures in our protocol every 3 months. Funding: N/A