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 like a cough or a 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. Any bacteria, fungi, or viruses present 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

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 like:

  • chest congestion
  • chronic cough
  • runny nose

It’s 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:

  • influenza
  • respiratory syncytial virus
  • Bordetella pertussis infection(whooping cough)
  • Staphylococcus aureus 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, like methicillin-resistant Staphylococcus aureus (MRSA).

Your doctor can perform this test in their office. There is no preparation required. 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’ll be asked to cough to produce secretions. Then you’ll 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.

The doctor will gently insert a small swab with a soft tip into your nostril. They’ll guide it to the back of the nose and twirl it 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. 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.

Your doctor should have the test results in a day or two.

Normal Results

A normal or negative test shows no disease-causing organisms.

Positive Results

A positive result means the organism causing your symptoms has been identified. Knowing what’s causing your symptoms can help your doctor choose the treatment.

Treatment for an upper respiratory disease depends on the organism causing it.

Bacterial Infections

Infections due to bacteria are usually treated with antibiotics.

If you’re infected with antibiotic-resistant bacteria, you may be hospitalized. You would be placed in a private room or 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 it from spreading. They should wash their hands frequently. Gloves should be worn when touching soiled garments or tissues.

Fungal Infections

A fungal infection may be treated with antifungal medications such as IV amphotericin B. Oral antifungal medications include fluconazole and ketoconazole.

In rare cases, a fungal infection will seriously damage part of your lung. Your doctor may need to remove the damaged area surgically.

Viral Infections

Viral infections don’t 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 like:

  • cough syrups for persistent coughing
  • decongestants for a stuffy nose
  • medications to reduce a high temperature

Avoid taking antibiotics for viral infections. An antibiotic won’t treat a viral infection, and taking it can make future bacterial infections more difficult to treat.