Testing distinguishes H1N1 from seasonal flu | NevadaAppeal.com

Testing distinguishes H1N1 from seasonal flu

Pam Graber
For the Nevada Appeal

Editor’s Note: This column appears in the Nevada Appeal Wednesday health pages throughout the flu season. Readers interested in knowing more about this topic are urged to visit http://www.flu.gov or http://www.cdc.gov/h1n1flu.

Q: How is H1N1 flu diagnosed?

A: H1N1 flu can be confirmed only with a real-time RT-PCR test (Reverse Transcriptase Polymerase Chain Reaction). To perform this test, a swab is used to swipe the inside of your nose or the back of your throat and sent off for laboratory confirmation. This accurate test is available only in certain laboratories, and it can take several days to get results.

This season, the CDC recommends real-time RT-PCR tests only for people who are so ill they are hospitalized, pregnant women, those with weakened immune systems, or for patients where testing could impact treatment decisions.

That leaves most of us who have had flu-like illness uncertain about what strain of flu we had.

Please remember that this season, the CDC tells us that most people with flu symptoms have mild illness and do not require medical care, testing or antiviral drugs. Besides, as of last September, over 99 percent of the circulating influenza viruses circulating in the U.S. were 2009 H1N1.

As of last month, worldwide virus identification was still highly identified as H1N1 (greater than 70 percent).

If you were one of the unlucky ones sick enough to see your doctor recently, you may have had what is known as an RIDT (Rapid Influenza Diagnostic Test). This test is also taken with the use of a swab used to swipe your nose or throat.

The advantage of RIDTs is they provide results within 30 minutes or less, a good timeframe within which clinical decisions can be made about your treatment. The disadvantage is that the rapid tests vary in their ability to detect flu viruses. False negatives are common, especially in adults. In addition, none of the rapid tests can distinguish H1N1 from other flu viruses. At best, an RIDT can determine that you have a type A or type B flu, but nothing more.

The wisdom here is that unless you were tested with the RT-PCR test, you don’t know for sure whether you had H1N1. If that is the case, it will not be harmful for you to get an H1N1 vaccination, and CCHHS highly recommends that you do.


There is no charge for H1N1 vaccinations

Where: Carson City Health and Human , 900 East Long St., Carson City

When: 8:30-11:30 a.m. and 1-4:30 p.m. every Thursday (closed for lunch)

WHERE: Montbleu Resort, 55 Highway 50, Stateline

WHEN: Noon-5 p.m. Thursday, Feb. 11

WHERE: Horizon Casino Resort, 50 Highway 50, Stateline

WHEN: 10 a.m.-2 p.m. Friday, Feb. 12

WHERE: Washoe Valley Christian Church, 145 Esmeralda Drive, Washoe Valley

WHEN: 1-4 p.m. Saturday, Feb. 13

• Pam Graber is the public information officer for Carson City Health and Human Services.