What Is an Influenza Swab?

Influenza, commonly called the flu, is a disease that can move from person to person relatively easily, and can infect a large number of people. Although most people quickly recover from the flu, some people, such as the elderly, are at risk of serious disease and even death. The flu virus has many different forms, some of which are more dangerous than others. An influenza swab, which is a method of sampling from a person, is a way for medical professionals to check if a patient has flu, and if so, what type of flu it is.

When the flu virus infects a person, it does so through the respiratory tract. The nose and throat are locations where the viral particles live and grow, and product symptoms like a runny nose, sore throat and cough. These locations are also the most accessible areas for a doctor to take samples from, and therefore an influenza swab is most often from these parts of the body.

Flu often moves quickly through populations and for public health reasons, some government health care agencies may want to track the movement of the disease. As the flu virus also mutates rapidly, producing new versions of the flu regularly, the type of flu a person has may also be important information for the public health system. Finally, a doctor may need to establish whether a person has flu or not in order to follow an appropriate course of treatment.

Swabs are tools that a medical professional uses to sample an area, typically for the presence of microbes. They often have long handles with a soft swab on the end, made of material or even of plastic, and are sterile, so that the test only analyzes the microbes present on the sampling area. During an influenza swab procedure, the doctor generally inserts the end of the swab into the nose of the patient and rotates the influenza swab so it collects as much mucus as possible. The doctor may insert the swab all the way through the nose into the top of the throat to sample that area, if it appears to have more viral growth than inside the nose itself.

Doctors have several different ways to test swabs for the presence of the influenza virus. The test that takes days to a week to complete is viral culture, where the viral particles are grown in the lab in human cells. Quicker tests include analyzing the sample for the presence of the genetic material in influenza, or antigen tests. Antigens are molecules that are part of the virus that are specific to that virus, and some commercial tests contain antibodies that can identify the presence of antigens by linking to them. These types of test can take less than an hour to complete, but may not be as accurate as viral culture.