At-home strep tests offer a convenient initial screening for Streptococcus pyogenes, the bacterium responsible for strep throat. These tests help individuals determine if their symptoms might be due to a strep infection without an immediate doctor’s visit. Their increased availability allows for quick insights into potential illnesses from home. While these tests provide rapid results, they are primarily screening tools and do not replace a definitive medical diagnosis.
How At-Home Strep Tests Work
At-home strep tests use a throat swab to collect a sample. The swab gathers secretions from the back of the throat and tonsils where Streptococcus pyogenes bacteria, if present, reside. After collection, the swab is inserted into a test cartridge or mixed with a solution containing reagents designed to detect specific bacterial components.
These tests function as rapid antigen detection tests, identifying antigens, which are unique surface proteins or pieces of the Group A Streptococcus bacteria. The reagents in the test kit react with these antigens, leading to a visible indication, often a color change or a line appearing on a test strip. Results are available within 5 to 15 minutes. Many rapid strep tests, including those used at home, are not yet specifically approved by the Food and Drug Administration (FDA) for over-the-counter home use, though they employ the same technology used by healthcare professionals.
Understanding Your Test Results
Interpreting at-home strep test results involves observing the lines or indicators on the test device. A positive result shows two lines: a control line, which confirms the test worked correctly, and a test line, indicating the presence of Streptococcus pyogenes antigens. A single control line suggests a negative result, meaning the bacteria were not detected. If no control line appears, the test is considered invalid, and a new test should be performed.
While a positive result suggests a strep infection, these tests are screening tools and not a definitive diagnosis. Rapid strep tests have an accuracy rate of approximately 86% for detecting an infection when done correctly. False-negative results, where strep is present but the test indicates it is not, can occur, with negative results being about 95% accurate. Therefore, even with a negative result, symptoms might still be caused by strep or another condition requiring medical attention.
Next Steps After Testing
Regardless of the at-home strep test result, seeking professional medical consultation is recommended. A healthcare provider can perform confirmatory testing, such as a throat culture, which is more accurate than a rapid test and can detect infections a rapid test might miss. This step is important for a proper diagnosis and to determine the appropriate course of treatment, especially if antibiotics are needed.
Untreated strep throat carries serious health risks, including potential complications like rheumatic fever, an inflammatory disease that can affect the heart, joints, brain, and skin. Another possible complication is kidney inflammation, known as post-streptococcal glomerulonephritis. Prompt and accurate diagnosis and treatment with antibiotics are important to eradicate the bacterial infection and prevent long-term health issues. Therefore, if symptoms persist, worsen, or are severe, consulting a doctor without delay is important for patient safety and effective management.