How It Works


How flu likelihood is determined

Each combination of symptoms has a different likelihood of being influenza. The likelihoods in “Do I have the flu?” are based on several studies that looked at patients’ presenting symptoms, and whether or not they were ultimately diagnosed with the flu.1-4



How care options are determined


The Centers for Disease Control and Infectious Disease Society of America publish guidelines for diagnosis and treatment of the flu. According to these guidelines, certain groups of patients (like those with lung disease and those who have compromised immune systems) are more likely to have complications of the flu. In “Do I have the flu?” these patients are asked to come into clinic for a physical exam and detailed history. “Do I have the flu?” also incorporates questions from the Telephone Triage Protocols for Nurses to make sure that patients with other potentially worrisome symptoms (like chest pain or trouble breathing) are advised to seek immediate care.



  1. Afonso AM, Ebell MH, Gonzales R, Stein J, Genton B, Senn N. The use of classification and regression trees to predict the likelihood of seasonal influenza. Fam Pract. 2012;29(6):671-7.
  2. Ebell MH, Afonso AM, Gonzales R, Stein J, Genton B, Senn N. Development and validation of a clinical decision rule for the diagnosis of influenza. J Am Board Fam Med. 2012;25(1):55-6
  3. Zimmerman RK, Balasubramani GK, Nowalk MP, et al. Classification and Regression Tree (CART) analysis to predict influenza in primary care patients. BMC Infect Dis. 2016;16(1):50
  4. Ebell MH, Afonso A. A systematic review of clinical decision rules for the diagnosis of influenza. Ann Fam Med. 2011;9(1):69-77.