Nasopharyngeal culture
Nasopharyngeal culture is a sample of secretions from the uppermost part of the throat, behind the nose, to detect organisms that can cause disease.
Alternative Names
Culture - nasopharyngeal; Swab for respiratory viruses; Swab for Staph carriage
How the test is performed
You will be asked to cough before the test begins and then tilt your head back. A sterile cotton-tipped swab is gently passed through the nostril and into the nasopharynx, the part of the pharynx that covers the roof of the mouth. The swab is quickly rotated and then removed.
How to prepare for the test
There is no special preparation necessary.
How the test will feel
You may experience slight discomfort and may gag.
Why the test is performed
The test identifies viruses and bacteria that cause upper respiratory tract symptoms. Nasopharyngeal cultures are useful in identifying respiratory viruses, and specific bacteria such as:
-
Bordetella pertussis
-
Neisseria meningitidis
- Staphylococcus aureus
The culture may be used to help determine which antibiotic therapy is appropriate.
Normal Values
The presence of organisms commonly found in the nasopharynx is normal.
What abnormal results mean
The presence of any disease-causing virus, bacteria, or fungus means these organisms may be involved in your infection. Sometimes organisms like Staphylococcus aureus can be present without causing disease, but the test can identify resistant strains of this organism (methicillin-resistant Staphylococcus aureus, or MRSA
) and patients can be isolated when necessary.
What the risks are
There are no risks.
References
Hewlett EL. Whooping cough and other Bordetella infections. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia,PA: Saunders Elsevier; 2011:chap 321.
Updated: 12/12/2011
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.