Background: Ambulatory blood pressure monitoring (ABPM) is a standard screening tool for the diagnosis of hypertension in children, adolescents, and adults. However, there is confusion and misunderstanding about which guidelines can provide the most accurate diagnostic values. Local problem: At a large, free-standing pediatric hospital, ABPM testing was historically being conducted by both nephrology and cardiology departments. The nephrology service was using the American Heart Association (AHA) guidelines, published in 2014 for interpretation of results and for diagnosis of hypertension, whereas the cardiology service depended on the 2004 National High Blood Pressure Education Program (NHBEP) fourth report, which led to discrepancies in diagnosis of hypertension in this patient population. Methods: A nurse practitioner–led quality improvement project was designed and implemented to determine the best method of ABPM monitoring and test interpretation based on comparing results of patients using height, gender, and application of either the 2004 NHBEP fourth report or 2014 AHA guidelines. Interventions: Using a retrospective chart review, ABPM monitoring results from both cardiology and nephrology services were reviewed and compared to identify the most accurate methods and to recommend changes to practice. Results: Accuracy of interpretation for ABPM is best accomplished using the 2014 AHA guidelines. Conclusions: Using a single method of interpretation provides consistent diagnosis and treatment of hypertension in children. Nurse practitioners can apply this knowledge in other settings to manage hypertension and provide similar services in different settings, including primary care. [ABSTRACT FROM AUTHOR]