Integrating molecular detection into public health definitions

In Canada, most notifiable disease case definitions use only traditional non-molecular tests, such as culture or direct examination for pathogens and serological tests, as evidence of disease. Because nucleic acid tests are generally superior to traditional tests in terms of sensitivity and turnaround time, these newer assays are highly appealing approaches for diagnosing infectious diseases. However, interpretation of molecular assays is not straightforward and requires caution and a firm understanding of the technology to optimize adoption for public health purposes. Accepting nucleic acid testing as evidence for “probable cases” is a prudent approach, enabling the integration of these methodologies into existing public health notifiable disease case definitions.