SARS-CoV-2 has familiarized the public with concepts they seldom thought about before 2020, such as herd immunity and positivity rates. In the process, it has brought into focus the relationship between public health and medicine, and the role of diagnostic testing in each.
While the fields of public health and medicine complement one another, their primary goals and focus are not entirely the same. In medicine, the focus is on the health of the individual and clinical diagnosis. In public health, it is on the health of larger populations, and it calls for screening and surveillance.
Diagnostic testing is performed on a patient who is symptomatic in order to help determine what condition they have. It is only warranted if the result of the test is expected to change management of the patient or provide meaningful clinical information about the patient’s expected outcomes or prognosis.
Screening, on the other hand, refers to testing an asymptomatic population for a particular condition in order to identify those who have the condition, so that they can be treated early and prevent further spread. Successful screening programs rely on tests that can detect early, pre-symptom disease. Public health officials are often involved in screening programs either directly (e.g., providing personnel to go to the elementary school to conduct the hearing screenings) or indirectly (e.g., health education campaigns). Screening is not the same as primary prevention. That is, it does not prevent the disease from occurring. However, it can prevent poor outcomes from it (referred to as secondary prevention).
Infectious disease surveillance involves the healthcare delivery system, the public health laboratory, and the epidemiologist. All three contribute to the four basic components of surveillance: collection, analysis, dissemination and response. Collection and analysis can be conducted at the local, national or international level by public agencies as well as private industry. Surveillance may monitor cases of disease reported by clinicians or identified in laboratories, or it may monitor changes in practice or other behaviors of public health importance.
While public health testing and clinical diagnostics may involve similar or identical procedures, their unique functions are a matter of context: Is it an individual’s health or a public health issue being addressed? SEKISUI Diagnostics offers point-of-care tests which help with the clinical diagnosis of infections, e.g., flu, RSV, and strep. They assist in patient management and treatment, as well as infection control procedures. They include: