Treat or test first? Decision analysis of empirical antiviral treatment of influenza virus infection versus treatment based on rapid test results

J Clin Virol. 2002 Jul;25(1):15-21. doi: 10.1016/s1386-6532(00)00182-7.


Background: neuraminidase (NA) inhibitors have recently become available for treatment of influenza. Rapid antigen detection assays at 'point-of-care' may improve the accuracy of clinical diagnosis, but the value of these techniques in assisting with the appropriate use of antivirals remains controversial.

Objective: to compare the diagnostic utilities of two management strategies for influenza, empirical antiviral therapy versus therapy based on a positive rapid test result in pre-epidemic and epidemic periods.

Study design: a threshold decision analytic model was designed to compare these competing strategies and sensitivity analysis performed to examine the impact of diagnostic variables on the expected utility of the decision with a range of prior probabilities of infection between 1 and 50%.

Results: on the basis of the calculated sensitivity (77%) and specificity (95%) of a point-of-care test for influenza, pre-treatment testing was preferred and cost-effective in non-epidemic stage of the influenza cycle. The alternative strategy of empirical treatment produces a higher utility value during epidemics, but may result in overuse of antivirals for low-risk populations. The two strategies had equivalent efficacy when the probability of influenza was 42%.

Conclusions: Patients with flu-like illness, who present outside the influenza outbreak and are considered to be at low risk for influenza-related complications, should be tested to confirm the diagnosis before starting antiviral treatment with a NA inhibitor. The most important variables in the model were the accuracy of the clinical diagnosis and the pre-test probability of influenza. A threshold probability of influenza of 42% would dictate changing from the rapid testing strategy to a 'treat regardless' strategy.

Publication types

  • Comparative Study

MeSH terms

  • Antiviral Agents / therapeutic use*
  • Bayes Theorem
  • Computer Simulation*
  • Decision Support Techniques*
  • Humans
  • Influenza, Human / diagnosis*
  • Influenza, Human / drug therapy*
  • Neuraminidase / antagonists & inhibitors*


  • Antiviral Agents
  • Neuraminidase