B-144 Implementation of pediatric CKiD U25 eGFR calculations with or without Cystatin C in Epic Beaker

Abstract Background Historic calculation of estimated glomerular filtration rate (eGFR) for pediatric patients relies on the beside Schwartz equation which utilizes creatinine, height, age, and sex. Conventionally, eGFR values are not provided in LIS systems for pediatric patients due to the laboratory’s lack of access to patient height. Recently an updated eGFR equation (CKiD U25) was developed that utilizes sex, age, height, IDMS traceable creatinine values and/or cystatin C (cys) which more accurately matches measured GFR for pediatric patients. Under the recommendation of our pediatric nephrology faculty, our health system sought to implement automated eGFR calculations for pediatric patients to enhance patient care. This work describes implementation of logic in Epic Beaker to calculate eGFR using the CKiD U25 equation using creatinine, age, sex, and height with or without cys for patients 1-18 years old. Methods Four equations dependent on patient sex and age were built in Beaker for creatinine and cys and then reference ranges dependent on age (1-2 years or 2-18 years) were applied. Male creatinine eGFR equations used ranges 1-<12 years and 12-<18 years while cys eGFR equations used 1-<15 years and 15-<18 years. Both female creatinine and cys eGFR equations used ranges 1-<12 years and 12-<18 years. Two additional equations based on sex were used for the average of the creatinine and cys eGFRs. Height was retrieved from the patient’s medical record using a newly built Epic extension that gathers the most recent documented height measurement within 6 months. Logic rules were created to determine which equation to apply based on patient sex and age. Missing patient height or creatinine auto-populates comments stating the result is “unable to calculate”. Patients <1 year old are omitted from the calculations. Results LIS testing was performed to verify the following patient sex and age demographics and the correct equations applied: <1 year old, male and female 1-2 years, male and female 2-18 years, male and female >18 years. Each test patient was evaluated for calculation of the CKiD U25 eGFR with or without creatinine and cystatin C. Proper handling of missingness for creatinine, cys, and height demonstrated acceptable performance in the absence of key information. Once testing scenarios were complete, education was done by Pediatric Nephrology to lab stakeholders and pediatric providers. After implementation of the CKiD U25 eGFR, the Pediatric Nephrology team notified the Beaker Application Analyst that creatinine was not pulling into the cys eGFR equation. Autoverification rules were identified as the cause. The test build was modified to require a value or comment be entered for the creatinine component and the equation calculated before autoverification happens in the LIS. Conclusion Implementation of pediatric eGFR calculations using height as a variable is possible in Epic by using an extension for retrieval from the medical record into Beaker. Additionally, logic can be implemented to provide pediatric eGFR calculations in the presence or absence of cys and/or creatinine values. Successful implementation required coordination from Beaker Application Analysts, Medical Laboratory Specialists, and Pediatric Nephrologists for development, testing, education, and deployment.