What Is a Nasopharyngeal Culture?
A nasopharyngeal culture is a quick, painless test used to diagnose upper respiratory infections. These are infections that cause symptoms such as a cough or runny nose. The test can be completed in your doctor’s office.
A culture is a way of identifying infectious organisms by allowing them to grow in a laboratory. This test identifies disease-causing organisms that live in the secretions at the back of your nose and throat.
For this test, your secretions are collected using a swab. They may also be suctioned out using an aspirator. Then any bacteria, fungi, or viruses in the sample are given a chance to multiply. This makes them easier to detect.
Results from this test are generally available within 48 hours. They can help your doctor effectively treat your symptoms.
You may also hear this test referred to as a:
- nasopharyngeal or nasal aspiration
- nasopharyngeal or nasal swab
- nose swab
What Is the Purpose of a Nasopharyngeal Culture?
Bacteria, fungi, and viruses can all cause upper respiratory disease. Doctors use this test to find out what type of organism is causing upper respiratory symptoms such as:
- chest congestion
- chronic cough
- runny nose
It is important to figure out the cause of these symptoms before treating them. Some treatments are only effective for certain types of infection. Infections that can be identified using these cultures include:
- Bordetella pertussis (whooping cough)
- Staphylococcus aureus (staph) infections of the nose and throat
The results of a culture can also alert your doctor to unusual or potentially life-threatening complications. For example, they can be used to identify antibiotic-resistant strains of bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA).
How Is a Nasopharyngeal Culture Obtained?
Your doctor can perform this test in his or her office. There is no preparation required. You can wear street clothes during the test. If your doctor agrees, you can return to your normal activities afterward.
When you arrive, your doctor will ask you to sit or lie down comfortably. You will be asked to cough to produce secretions. Then you will need to tilt your head back to about a 70-degree angle. Your doctor may suggest that you rest your head against a wall or a pillow so you won’t be tempted to pull away during the collection.
The doctor will gently insert a small swab with a soft tip into your nostril. It will be guided to the back of the nose and twirled a few times to collect secretions. This may be repeated in the other nostril. You may gag a little. You may also feel some pressure or discomfort.
If a suction device is being used, the doctor will insert a small tube into your nostril. Then a gentle suction will be applied to the tube. Do not be scared of the machine. In general, people find suction more comfortable than a swab.
Your nose may feel irritated or bleed a little bit after the procedure. A low-cost humidifier may ease these symptoms.
What Will the Results Show?
Your doctor should have the test results in a day or two.
A normal or negative test shows no disease-causing organisms.
A positive result means that the organism causing your symptoms has been identified. Knowing what is causing your symptoms can help your doctor decide how to treat them.
Treating Upper Respiratory Infections
Treatment for upper respiratory disease depends on what organism is making you sick.
Infections due to bacteria are usually treated with antibiotics.
If you are infected with antibiotic-resistant bacteria, you may be hospitalized. You would be placed in a private room or in a room with other patients with the same infection. Then very strong antibiotics would be used until your infection was under control. For example, MRSA is usually treated with intravenous (IV) vancomycin.
If you have MRSA, your family should be careful to prevent its spread. They should wash their hands frequently. Gloves should be worn when touching soiled garments or tissues.
A fungal infection may be treated with anti-fungal medications. Oral medications include fluconazole and ketoconazole. There is also IV amphotericin B.
In rare cases, a fungal infection will seriously damage part of your lung. Your doctor may need to surgically remove the damaged area.
Viral infections do not respond to treatment with antibiotics or antifungals. They usually last a week or two and then disappear on their own. Doctors generally prescribe comfort measures such as:
- cough syrup for persistent coughing
- decongestants for a stuffy nose
- medication to reduce temperature
Do not insist that your doctor prescribe an antibiotic for a viral infection. It will not improve your health. It could, however, make future bacterial infections more difficult to treat.