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. It may cause severe fits of rapid coughing. In serious cases, the coughing may last until all the air is gone from your lungs. This forces you to gasp for air, which makes a loud "whooping" sound. After a coughing fit, your breathing becomes normal until you start coughing again.

Whooping cough is easily spreads 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 have had all their childhood vaccines against whooping cough. Babies less than a year old who get whooping cough often need hospital care.

Whooping cough tests can help diagnose the disease early. This is important because treatment is most helpful when it's started before serious coughing fits begin.

The best way to protect against whooping cough is with pertussis vaccination. Vaccinated people may still get whooping cough, 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 symptoms of whooping cough. You or your child may also need a test if you've been exposed to someone who has whooping cough and you have symptoms of a cold.

Symptoms of whooping cough usually happen in three stages. It's best to get tested in the first stage, when treatment works best. In this stage, symptoms are like those of a common cold. They can last for one to two weeks and usually include:

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

In the second stage, the symptoms are more serious and may include:

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

Coughing fits may get worse and continue for 10 weeks or more. With milder illness, you may not "whoop." The infection is usually milder in teens and adults, especially those who have had the vaccine.

In the third stage, the cough will be milder, and you'll cough less often. But recovery can be slow.

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 to four weeks after coughing begins. A PCR test checks your fluid sample for genetic material from 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:

• Nasal aspirate or wash. Your provider will insert a saline solution into your nose, then remove the sample with gentle suction.
• Swab test. Your provider will use a special swab to take a sample from deep in your nose.

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.

Are there any risks to the tests?

There is very little risk to whooping cough tests.

• A nasal aspirate or wash may feel uncomfortable. These effects are temporary.
• For a swab test, you may feel a gagging sensation or even a tickle when your nose is swabbed.
• 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, your provider will use your test results, your symptoms, and whether or not it was likely that you were exposed 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 week 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.