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Tests and diagnosis
By Mayo Clinic staffYour child's doctor will start with a physical exam that will include:
- Using a lighted instrument to look at your child's throat and likely his or her ears and nose, which may also be sites of infection
- Checking for a rash known as scarlatina, which is associated with some cases of strep throat
- Gently feeling (palpating) your child's neck to check for swollen glands (lymph nodes)
- Listening to his or her breathing with a stethoscope
- Checking for enlargement of the spleen (for consideration of mononucleosis which also inflames the tonsils)
Throat swab
With this simple test, the doctor rubs a sterile swab over the back of your child's throat to get a sample of secretions. The sample will be checked in a lab for streptococcal bacteria.
Many clinics are equipped with a lab that can get a test result within a few minutes. However, a second more reliable test is usually sent out to a lab that can return results within 24 to 48 hours.
If the rapid in-clinic test comes back positive, then your child almost certainly has a bacterial infection. If the test comes back negative, then your child likely has a viral infection. Your doctor will wait, however, for the more reliable out-of-clinic lab test to determine the cause of the infection.
Complete blood cell count (CBC)
Your doctor may order a CBC with a small sample of your child's blood. The result of this test, which can often be completed in a clinic, produces a count of the different types of blood cells. The profile of what's elevated, what's normal or what's below normal can indicate whether an infection is more likely caused by a bacterial or viral agent. A CBC is not often needed to diagnose strep throat. However, if the strep throat lab test is negative, the CBC may be needed to help determine the cause of tonsillitis.
- Fact sheet: Tonsils and adenoids. American Academy of Otolaryngology — Head and Neck Surgery. http://www.entnet.org/HealthInformation/tonsilsAdenoids.cfm. Accessed April 23, 2012.
- Fact sheet: Tonsillitis. American Academy of Otolaryngology — Head and Neck Surgery. http://www.entnet.org/HealthInformation/tonsillitis.cfm. Accessed April 23, 2012.
- Kliegman RM, et al. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa.: Saunders Elsevier; 2011. http://www.mdconsult.com/das/book/body/208746819-6/0/1608/0.html. Accessed April 23, 2012.
- Ferri FF. Ferri's Clinical Advisor 2012:5 Books in 1. Philadelphia, Pa.: Mosby Elsevier; 2012. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-323-05611-3..C2009-0-38601-8--TOP&isbn=978-0-323-05611-3&uniqId=291436269-101. Accessed April 23, 2012.
- McPhee SJ, et al. Current Medical Diagnosis & Treatment 2012. 51st ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=1. Accessed April 22, 2012.
- Tonsillopharyngitis. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/ear_nose_and_throat_disorders/oral_and_pharyngeal_disorders/tonsillopharyngitis.html. Accessed April 23, 2012.
- Tagliareni JM, et al. Tonsillitis, peritonsillar and lateral pharyngeal abscesses. Oral and Maxillofacial Surgery Clinics of North America. 2012;24:197.
- Fact sheet: Tonsillectomy procedures. American Academy of Otolaryngology — Head and Neck Surgery. http://www.entnet.org/HealthInformation/tonsillectomyProcedures.cfm. Accessed April 23, 2012.
- Mandell GL, et al. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-443-06839-3..X0001-X--TOP&isbn=978-0-443-06839-3&uniqId=230100505-57. Accessed April 23, 2012.
- Fact sheet: Tonsils and adenoids: PostOp. American Academy of Otolaryngology — Head and Neck Surgery. http://www.entnet.org/HealthInformation/tonsilsAdenoidsPostop.cfm. Accessed April 23, 2012.
- Stopping the spread of germs at home, work and school. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/protect/stopgerms.htm. Accessed June 24, 2012.
- Hoecker JL (expert opinion). Mayo Clinic, Rochester, Minn. May 15, 2012.
- Orvidas LJ (expert opinion). Mayo Clinic, Rochester, Minn. May 15, 2012.
- Baugh RF, et al. Clinical Practice Guideline: Tonsillectomy in children. Otolaryngology — Head and Neck Surgery. 2011;144:S1.
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