Source review date: September 20, 2026. This date is not the publication date of a news item or a date of scientific approval.
Can a diagnosis be made from symptoms alone?
Fever, cough, and nasal congestion are common to several respiratory infections. Testing may help some patients choose care or treatment; the name of the virus cannot be guessed from the severity of the cough alone.
Which test?
An antigen test detects components of the virus and is usually faster. A molecular test, such as PCR, examines the virus’s genetic material and is usually more sensitive. Some tests examine several agents at the same time; this does not mean they cover all viruses.
Does a negative rapid test mean I do not have the disease?
Not necessarily. A negative antigen result can occur even when an infection is present. If symptoms continue or the risk of severe illness is high, consult a physician about repeating the test or having a molecular test.
Who should seek follow-up sooner?
People at risk of severe illness should be evaluated sooner, because timely initiation of treatment is important for some infections. Shortness of breath, chest pain, or severe dehydration requires immediate evaluation; do not wait for the test result.
Limits of the evidence
This text is a summary of an educational guide, not a report on the prevalence of infection in Mashhad. The choice of test depends on the clinical question; not all colds require extensive testing.
Sources and their dates
CDC; Respiratory Virus Testing — August 18, 2025
WHO; Questions about Respiratory Infections and HMPV — January 10, 2025