The accuracy of rapid tests and especially sensitivity is highly dependent on the quality of sampling and the time from onset of the symptoms
The diagnostic test result is only as good as the quality of the sample
To detect respiratory infection pathogens, sampling should be done during viremia within six days from the onset of symptoms. Most preferably it should be done within five days. Viral titres go down in due time and usually viral antigens are no longer detectable after 6‒7 days. Maximum amount of virus is typically present on days 1‒3.
Ask the patient to blow their nose when possible
Bend the patient´s head backward
Swiftly insert the swab into the nostril. The depth of insertion is around 4–8 cm for children and 8–12 cm for adults.
Rotate the swab against the nasopharyngeal mucosa and remove the swab
Take a sample from the nasopharynx with a flocked swab and insert the swab into a test tube
Dispense sample buffer and vortex
Insert the barcoded test tube into the analyser for automated analysis