ICD90CM claims data are insufficient for influenza surveillance.

Influenza and Influenza like illness are representative of a class of epidemic infectious diseases that have important public health implications. Early detection via Biosurveillance can speed life saving public heath responses. In the United States Biosurveillance is typically conducted using ICD9 coded visit diagnoses and uncoded chief complaint data. To determine the accuracy of ICD9 diagnoses using laboratory confirmed cases as the gold standard. We determined the sensitivity and specificity of ICD9 in detecting laboratory confirmed vs unconfirmed Influenza. ICD9-CM had a low 66.2% Positive Predictive Value (precision) for Influenza and a low 45.6% Sensitivity (recall) for Influenza. ICD9-CM proved insufficient alone for use in biosurveillance.