Whooping Cough Tests

What are whooping cough tests?

A whooping cough test usually uses fluid from your nose to help diagnose whooping cough, also known as pertussis.

Whooping cough is a serious bacterial infection in your respiratory system that may cause severe fits of rapid coughing. In serious cases, the coughing may last until all the air is gone from your lungs. This results in the "whooping" sound that the infection is named after.

Whooping cough is easily spread from person to person, usually by coughing or sneezing. You can get it at any age, but the illness is most serious in babies and children who are too young to get their childhood vaccines against whooping cough. Babies who are less than a year old who get whooping cough often need hospital care.

The best way to protect against whooping cough is with the pertussis vaccination. Vaccinated people may still get the infection, but their illness is usually milder and shorter.

Other names: pertussis test, bordetella pertussis culture, PCR, antibodies (IgA, IgG, IgM)

What are the tests used for?

Whooping cough tests are used to find out whether you or your child has whooping cough. Getting diagnosed and treated in the early stages of infection may make your symptoms less severe and help prevent the spread of the disease.

Why do I need a whooping cough test?

Your health care provider may order a whooping cough test if you or your child has been exposed to someone with whooping cough or has symptoms of the infection. Symptoms usually happen in three stages. In the first stage, symptoms are like those of a common cold. They can last for one or two weeks and usually include:

• Runny nose.
• Mild fever.
• Mild cough (babies may not cough).
• Pauses in breathing, called apnea, especially in babies.

In the second stage, which can last 10 weeks or more, the symptoms are more serious and may include:

• Severe coughing fits followed by a high-pitch "whoop" sound.
• Coughing so hard it causes vomiting.
• Feeling very tired after coughing fits.

The third stage marks the beginning of the recovery. Your cough may be milder, and you may cough less often.

A provider may order a test during any one of these stages. They may order it even if you don't have the "whooping" sound when you cough, especially if you've been exposed to someone with this infection.

The infection is usually milder in teens and adults, especially those who have had the vaccine.

What happens during a whooping cough test?

Two types of tests are commonly used to diagnose whooping cough. Both tests use a sample of fluid and cells from the back of your nose. Your provider may order one or both of these tests:

• Bacteria culture test. This test is most accurate when it's done during the first two weeks after coughing begins. Your fluid sample is sent to a lab. Cells in the sample are grown until there are enough to test. The sample is then checked for whooping cough bacteria. Test results may take up to a week.
• PCR (polymerase chain reaction) test. This test is most accurate when it's done in the first three weeks after coughing begins. A PCR test checks your fluid sample for DNA left behind by the whooping cough bacteria. Results may be ready in as soon as two hours.

For a bacterial culture or a PCR test, your provider will use one of these ways to gather a sample of fluid and cells from your nose:

• Swab test. Your provider will use a special swab to take a sample from your nose, throat, or cheek.
• Nasal aspirate or wash. Your provider will squirt a saline solution (salt water) into your nose and remove the sample with gentle suction.

Blood tests that look for antibodies to whooping cough are generally not used to diagnose infections. Researchers use these tests to study the spread of whooping cough in the community. Whooping cough antibodies are proteins in your blood that your immune system makes to fight the infection. A blood antibody test may be done from 2 to 12 weeks after coughing begins. So, the test may be used in later stages when culture and PCR tests may not give accurate results.

If you have a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for a whooping cough test?

You don't need any special preparations for a whooping cough test. However, if you have taken antibiotics in the days leading up to your test, let your provider know. This may affect your test results.

Are there any risks to the tests?

There is very little risk to whooping cough tests.

• A nasal aspirate or wash may feel uncomfortable.
• A swab test may tickle or cause you to gag.
• For a blood test you may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

For a bacteria culture test:

• A positive result means that you have whooping cough.
• A negative result may mean that you don't have whooping cough, but it doesn't rule it out. If your test sample was taken too late or if you took antibiotics before your test, the results may not be accurate.

For a PCR test:

• A positive result means that genetic material from the whooping cough bacteria was found in your test sample, and you probably have whooping cough. But the PCR test may have found material from other related bacteria and mistaken it for whooping cough bacteria.
• A negative result means that you probably don't have whooping cough, but it doesn't rule it out. It's possible that your sample didn't have enough bacteria for the test to be accurate.

To make a diagnosis for whooping cough, your provider can use your:

• Test results
• Symptoms
• Medical history
• Potential exposures to whooping cough

Blood testing for whooping cough antibodies is not recommended for diagnosing a whooping cough infection. If you had this test and you were vaccinated, certain antibodies will show up in your test results. If a blood test finds certain other antibodies, it may mean you had a recent whooping cough infection.

Whooping cough is treated with antibiotic medicine. Antibiotics can make your infection less serious if you start treatment before your cough gets bad. Treatment may also help prevent you from spreading the disease to others. If you have questions about your test results or treatment, talk with your provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about whooping cough tests?

Vaccination is the best protection against whooping cough, but it doesn't give lifetime protection. Ask your provider when you and your child need to be vaccinated. Your provider can also answer any questions you have about possible vaccine side effects.

If you're pregnant, you should be vaccinated between the 27th and 36th weeks of your pregnancy. If you're vaccinated during each pregnancy, you will pass protection against whooping cough to your baby for the first months of life before the baby can be vaccinated.

You can also take steps to avoid getting or spreading whooping cough. These include:

• Avoiding close contact with those who have whooping cough.
• Staying at home if you or your child has whooping cough.
• Covering your mouth and nose when coughing or sneezing.
• Thoroughly washing your hands, especially before and after handling food or going to the bathroom.