False negatives for flu tests increase during outbreaks

ajc.com

Flu season came early to Georgia and it has been hitting locals hard.

There has been a total of 12 confirmed influenza related deaths in the state this season according to the Georgia Department of Public Health. All the recorded deaths have occurred among individuals age 50 and older and nine were over the age of 65, a population which is particularly vulnerable to the infection.

Read More: Flu deaths reach 12 in Georgia as flu remains widespread

About 40 percent of people in the Atlanta metro area have had some sort of respiratory illness in the last 60 days, said Dr. Charles Lutin, a doctor for American Family Care in Marietta.

Flu-like symptoms such as fever, chills, cough, sore throat, muscle aches, headache and fatigue have sent record numbers of individuals to emergency rooms, health clinics and doctor's offices, but the tests for the flu don't always give confirmation of the illness.

At AFC locations nationwide, doctors have seen some patients with obvious symptoms that do not get a positive test result for the flu.

Studies show that about 4 out of 10 individuals who test negative for the flu have the virus, Dr. Lutin said.

Doctors use a swab in the nose to test for the flu, but the test requires a certain amount of antigen linked to the virus to get a positive result. For some individuals, the sample isn’t broad enough and they appear to have a negative result, said Lutin.

False negatives tend to be higher at the beginning of the flu season or during a major outbreak, according to reports from the CDC and FDA, but some tests are more accurate than others.

As a result, even if a patient initially tests negative for the flu but shows obvious signs of infection, doctors will proceed with treatment.

The highly-mutable H3N2 flu strain this season has been particularly challenging, making early treatment a necessity. Antiviral drugs like Tamiflu or Relenza can help sufferers fight the flu virus, particularly when taken within two days of getting sick.