Table of ContentsView AllTable of ContentsSelf-ChecksLabs and TestsImagingDifferential DiagnosesFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Self-Checks
Labs and Tests
Imaging
Differential Diagnoses
Frequently Asked Questions
Diagnosis ofstrep throatcannot be based solely on clinicalsigns and symptoms, and additional tests are required for positive identification of theStreptococcus pyogenesbacteria thatcause the condition. A rapid strep test can yield same-day results, but it may take a couple of days to get the results of a throat culture, which is more accurate. A definitive diagnosis is important becausetreatmentcan help prevent possible long-term complications, such as heart and kidney disease.
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The early signs and symptoms of strep throat overlap with those of most upper respiratory infections. While you can’t diagnose yourself with strep, you can look for the following, which may hint that strep throat could be affecting you or your child:
There are a few important symptoms that could indicate a persistent or worsening infection:
Because strep throat causes signs and symptoms that are so similar to those of viral infections and other bacterial infections, the best way to confirm the diagnosis is with a laboratory test. Tests can detect either theStreptococcus pyogenesorganism or markers that signal the presence of the organism in the back of your throat.
Throat Culture
A throat culture has long been considered the diagnostic gold standard of strep throat infection, with the main disadvantage being a 24- to 48-hour delay in culture results.
Streptococcus pyogeneshas a unique feature that allows it to break open red blood cells. When the bacteria are grown on these plates, there will be a clearing of red blood cells on the petri dish ifStreptococcus pyogenesbacteria is present in the sample.
Rapid Antigen Detection Tests
Rapid antigen tests have much lower sensitivity than throat cultures, which means that they are more likely to mistakenly miss strep infection than throat cultures are.
It is estimated that rapid antigen tests have about a 14 to 20% false-negative rate.For this reason, if there is a strong chance of strep throat infection, it is recommended that a negative result from a rapid antigen test be followed up with a throat culture (for confirmation).
Rapid antigen detection tests are not associated with a false positive rate, which means that if they come back positive, there is high certainty that you have a strep throat infection.
Negative Strep Throat Test: What Else Mimics Strep?
Imaging tests are not routine in the diagnosis of uncomplicated strep throat infection. However, tests such as X-ray, CT, MRI, or ultrasound may be necessary to evaluate serious complications of strep throat infections, such as kidney or heart involvement. These complications are rare and primarily seen in untreated patients.
Most upper respiratory infections can begin with the same signs and symptoms as strep throat. Here are some of the illnesses that are considered when you are being evaluated for a possible strep throat:
Less often, primary HIV, HSV, gonorrhea, diphtheria, or tularemia can cause symptoms similar to those of strep throat.
Frequently Asked QuestionsNo. Early symptoms are too similar to other upper respiratory illnesses, so a lab test for bacteria is necessary to confirm the diagnosis andstart antibiotics, such aspenicillin.If your strep test comes back positive, your doctor will start you on antibiotics. You’re no longer considered contagious after 24 hours on antibiotics.However, finish the entire course of treatment to avoid complications, likerheumatic fever.Both cause pain and make it hard to swallow, but unlike a viral infection, strep usually includesswollen lymph nodesand a high fever. You may also have white spots on the throat or red spots in the mouth, a rash on the neck, and symptoms that last more than 48 hours.
No. Early symptoms are too similar to other upper respiratory illnesses, so a lab test for bacteria is necessary to confirm the diagnosis andstart antibiotics, such aspenicillin.
If your strep test comes back positive, your doctor will start you on antibiotics. You’re no longer considered contagious after 24 hours on antibiotics.However, finish the entire course of treatment to avoid complications, likerheumatic fever.
Both cause pain and make it hard to swallow, but unlike a viral infection, strep usually includesswollen lymph nodesand a high fever. You may also have white spots on the throat or red spots in the mouth, a rash on the neck, and symptoms that last more than 48 hours.
How Strep Throat Is Treated
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Strep Throat: All You Need to KnowCenters for Disease Control and Prevention.Pharyngitis (strep throat).Cohen JF, Bertille N, Cohen R, Chalumeau M.Rapid antigen detection test for group A streptococcus in children with pharyngitis.Cochrane Database Syst Rev.2016 Jul 4;7(7):CD010502. doi:10.1002/14651858Sadowski A, Dougherty J.Not All Sore Throats Are Pharyngitis. Clin Pract Cases Emerg Med. 2017;1(4):280-282. doi:10.5811/cpcem.2017.5.33316Stanford Children’s Hospital.What you need to know about strep throat.Luo R, Sickler J, Vahidnia F, Lee Y-C, Frogner B, Thompson M.Diagnosis and management of group a streptococcal pharyngitis in the United States, 2011–2015.BMC Infect Dis. 2019;19(1):193. doi:10.1186%2Fs12879-019-3835-4Additional ReadingAtkinson TP, Centor RM, Xiao L, et al.Analysis of the tonsillar microbiome in young adults with sore throat reveals a high relative abundance of Fusobacterium necrophorum with low diversity.PLoS One. 2018 Jan 19;13(1):e0189423. doi: 10.1371/journal.pone.0189423. eCollection 2018.Cohen JF, Bertille N, Cohen R, Chalumeau M. Rapid antigen detection test for group A streptococcus in children with pharyngitis. Cochrane Database Syst Rev. 2016 Jul 4;7:CD010502. doi: 10.1002/14651858.CD010502.pub2.
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Strep Throat: All You Need to KnowCenters for Disease Control and Prevention.Pharyngitis (strep throat).Cohen JF, Bertille N, Cohen R, Chalumeau M.Rapid antigen detection test for group A streptococcus in children with pharyngitis.Cochrane Database Syst Rev.2016 Jul 4;7(7):CD010502. doi:10.1002/14651858Sadowski A, Dougherty J.Not All Sore Throats Are Pharyngitis. Clin Pract Cases Emerg Med. 2017;1(4):280-282. doi:10.5811/cpcem.2017.5.33316Stanford Children’s Hospital.What you need to know about strep throat.Luo R, Sickler J, Vahidnia F, Lee Y-C, Frogner B, Thompson M.Diagnosis and management of group a streptococcal pharyngitis in the United States, 2011–2015.BMC Infect Dis. 2019;19(1):193. doi:10.1186%2Fs12879-019-3835-4Additional ReadingAtkinson TP, Centor RM, Xiao L, et al.Analysis of the tonsillar microbiome in young adults with sore throat reveals a high relative abundance of Fusobacterium necrophorum with low diversity.PLoS One. 2018 Jan 19;13(1):e0189423. doi: 10.1371/journal.pone.0189423. eCollection 2018.Cohen JF, Bertille N, Cohen R, Chalumeau M. Rapid antigen detection test for group A streptococcus in children with pharyngitis. Cochrane Database Syst Rev. 2016 Jul 4;7:CD010502. doi: 10.1002/14651858.CD010502.pub2.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Strep Throat: All You Need to KnowCenters for Disease Control and Prevention.Pharyngitis (strep throat).Cohen JF, Bertille N, Cohen R, Chalumeau M.Rapid antigen detection test for group A streptococcus in children with pharyngitis.Cochrane Database Syst Rev.2016 Jul 4;7(7):CD010502. doi:10.1002/14651858Sadowski A, Dougherty J.Not All Sore Throats Are Pharyngitis. Clin Pract Cases Emerg Med. 2017;1(4):280-282. doi:10.5811/cpcem.2017.5.33316Stanford Children’s Hospital.What you need to know about strep throat.Luo R, Sickler J, Vahidnia F, Lee Y-C, Frogner B, Thompson M.Diagnosis and management of group a streptococcal pharyngitis in the United States, 2011–2015.BMC Infect Dis. 2019;19(1):193. doi:10.1186%2Fs12879-019-3835-4
Centers for Disease Control and Prevention.Strep Throat: All You Need to Know
Centers for Disease Control and Prevention.Pharyngitis (strep throat).
Cohen JF, Bertille N, Cohen R, Chalumeau M.Rapid antigen detection test for group A streptococcus in children with pharyngitis.Cochrane Database Syst Rev.2016 Jul 4;7(7):CD010502. doi:10.1002/14651858
Sadowski A, Dougherty J.Not All Sore Throats Are Pharyngitis. Clin Pract Cases Emerg Med. 2017;1(4):280-282. doi:10.5811/cpcem.2017.5.33316
Stanford Children’s Hospital.What you need to know about strep throat.
Luo R, Sickler J, Vahidnia F, Lee Y-C, Frogner B, Thompson M.Diagnosis and management of group a streptococcal pharyngitis in the United States, 2011–2015.BMC Infect Dis. 2019;19(1):193. doi:10.1186%2Fs12879-019-3835-4
Atkinson TP, Centor RM, Xiao L, et al.Analysis of the tonsillar microbiome in young adults with sore throat reveals a high relative abundance of Fusobacterium necrophorum with low diversity.PLoS One. 2018 Jan 19;13(1):e0189423. doi: 10.1371/journal.pone.0189423. eCollection 2018.Cohen JF, Bertille N, Cohen R, Chalumeau M. Rapid antigen detection test for group A streptococcus in children with pharyngitis. Cochrane Database Syst Rev. 2016 Jul 4;7:CD010502. doi: 10.1002/14651858.CD010502.pub2.
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