What is a ASO test?
The ASO test measures the level of antistreptolysin antibodies in the bloodstream, which are produced by your immune system when it encounters streptolysin O toxin created by group A Streptococcus (GAS) bacteria. The production of these antibodies is a response to the GAS bacteria and helps your body fight against the infection.
The antistreptolysin O (ASO) titer test measures the amount of antistreptolysin antibodies in the blood, which indicates whether you have a strep infection. The results of this test enable the doctor to identify and prevent potential post-streptococcal complications.
What is the ASO test used for?
The ASO test, also known as the antistreptolysin O titer test, is used to evaluate the levels of antibodies that the body produces in response to the group A Streptococcus (GAS) bacteria. However, sometimes a strep infection may not show symptoms, and it could result in post-streptococcal complications. To prevent such complications, doctors perform the ASO test.
Why do I need an ASO test?
If you show symptoms of post-streptococcal complications such as rheumatic fever, glomerulonephritis, or bacterial endocarditis, your physician may suggest an ASO test. Medical professionals use the antistreptolysin O titer test to evaluate the levels of antistreptolysin antibodies in your body, which can help diagnose whether you are experiencing post-streptococcal complications.
What happens during an ASO test?
The healthcare provider may instruct you to fast for six hours before taking the ASO test. The procedure involves drawing blood from your inner arm vein with a fine needle, and the blood is then collected in a tube by the lab technician. The tube will be sent to the laboratory for examination.
What is the normal range of ASO?
The normal ASO test range for adults is below 200, while for children under five years, it is below 100. If your results exceed these levels, it may indicate that you have a post-streptococcal complication. Sometimes, even if your ASO test results are normal if you show symptoms of a post-streptococcal complication, your physician may recommend a follow-up test (second test).
Is it necessary to fast before an ASO blood test?
Before undergoing the antistreptolysin O titer test, the physician may advise you to fast for six hours to provide a blood sample.
