In Denial: Symptom Negation in New York City Emergency Department Chief Complaints

Introduction In July 2016, 77% of ED data was transmitted daily via Health Level 7 (HL7) messages, compared to only 27% in July 2015 (Figure). During this same period, chief complaint (CC) word count has increased from an average of 3.8 words to 6.0 words, with a twenty-fold increase in the appearance of the word “denies” in the chief complaint (Figure). While HL7 messages provide robust chief complaint data, this may also introduce errors that could lead to symptom and syndrome misclassification.