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Whooping Cough Tests
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Lab Tests

Whooping Cough Tests

Whooping cough (pertussis) is a serious bacterial respiratory infection diagnosed primarily through nasal fluid samples to identify the presence of the bacteria.

What are whooping cough tests?

Whooping cough is a bacterial infection that causes severe coughing fits, often followed by a "whooping" sound. It is highly contagious and most serious in infants. The best protection is the pertussis vaccination.

Why do I need a whooping cough test?

Your provider may order a test if you have been exposed to the infection or exhibit symptoms. Symptoms occur in three stages:

  • Stage 1: Cold-like symptoms (runny nose, mild fever, mild cough).
  • Stage 2: Severe coughing fits, vomiting after coughing, and extreme fatigue.
  • Stage 3: Recovery, where the cough becomes milder.

What happens during a whooping cough test?

Two common tests use fluid from the back of the nose:

  • Bacteria culture test: Most accurate within the first two weeks of coughing. The sample is grown in a lab to check for bacteria.
  • PCR (polymerase chain reaction) test: Most accurate within the first three weeks. It checks for DNA left behind by the bacteria.

Samples are collected via a nasopharyngeal swab (a long swab inserted into the nostril) or a nasal aspirate/wash (using saline solution and suction).

Blood tests for antibodies are generally not used for diagnosis, as they are more useful for research or identifying past infections.

What do the results mean?

  • Culture test: A positive result confirms whooping cough. A negative result does not rule it out, especially if taken late or after antibiotic use.
  • PCR test: A positive result indicates the presence of bacterial genetic material. A negative result suggests you likely do not have the infection, though it is possible the sample lacked sufficient bacteria.

Is there anything else I need to know?

In rare cases, a bronchoalveolar lavage (BAL) may be performed during a bronchoscopy to collect a sample from the lungs. This is used if you are not improving with treatment or if the provider suspects another respiratory illness like pneumonia or parapertussis.

Frequently Asked Questions

The procedure is generally uncomfortable but not severely painful. For a nasopharyngeal swab, a long, flexible swab is inserted through one nostril and guided along the bottom of the nose to the back of the throat. This can cause a sneeze reflex, a gagging sensation, or mild irritation. For a nasal aspirate, a saline solution is gently suctioned from the nose. The entire process takes only a few seconds. It is safe for infants and adults, though infants may cry during the procedure due to the sensation rather than pain.
negative test does not definitively rule out whooping cough, especially if the sample was collected late in the course of the illness. The bacteria culture test is most accurate within the first two weeks of coughing, and the PCR test is most accurate within the first three weeks. After this window, the bacterial load in the nose decreases, making it harder to detect. Additionally, if you have already started taking antibiotics, the bacteria may be suppressed, leading to a false-negative result. Your provider may diagnose based on symptoms and exposure history even if the test is negative.
Yes, it is possible to be contagious even with a negative test, particularly if the test was taken late in the infection or if the test sensitivity was low at that time. Whooping cough is highly contagious during the first few weeks of the coughing phase. If you have been exposed to a confirmed case or have classic symptoms, your healthcare provider may recommend preventive antibiotics (such as azithromycin) regardless of the test result to prevent spreading the infection to vulnerable populations, such as infants and pregnant women.
Timing is critical for accurate diagnosis. The bacteria culture test is the gold standard but is only highly sensitive during the first two weeks of coughing. The PCR test detects bacterial DNA and remains accurate for up to three weeks after the cough starts. If you present after the first three weeks, both tests become less reliable because the bacteria are no longer present in sufficient quantities in the nasal passages. In later stages, diagnosis is often clinical, based on the pattern of coughing fits and exposure history, rather than laboratory confirmation.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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