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Antistreptolysin O


What is it?

Antistreptolysin O is also called ASO. It is an antibody found in your blood. An antibody is a protein in your blood that finds and destroys material caused by infections or poisons. The ASO antibody shows you have had an infection like strep throat, caused by the Streptococcus bacteria. This test is done to see if you have the ASO antibody in your blood.

Why do I need it?

Some illnesses are caused by having had a Streptococcus bacteria infection sometime in the past. These diseases may involve the heart, such as in rheumatic fever or scarlet fever. It may also include some kidney diseases. ASO shows up in the blood after a streptococcus infection. The presence of ASO does not tell which disease you have now. It only tells there has been a streptococcus infection. The results of the test may be helpful to plan the treatment for your illness. Several ASO tests may need to be done over a period of weeks.

How do I get ready for the test?

Your caregiver will tell you when to have your blood test done. The blood test may be done before or after eating. Caregivers will tell you if you should not take your medicines until after your blood is taken.

How is the specimen collected?

A caregiver will put a wide rubber strap around your arm and tighten it. Your skin will be cleaned with alcohol. A small needle attached to a special test tube will be put into a vein in your arm or hand. The tube has suction to pull the blood into it. When the tube is full, the rubber strap, needle and tube are removed. The caregiver will press a piece of cotton where the needle was removed. You may be asked to hold the cotton on the site for a few minutes to help stop the bleeding. Tape may then be put over the cotton on your arm.

What do I do after the test?

You may remove the tape and cotton in about 20 to 30 minutes. Call your caregiver to get the results of your test. Your caregiver will explain what your test results mean for you. Follow the instructions of your caregiver.

Care Agreement

You have the right to help plan your care. To help with this plan, you must learn about your lab tests. You can then discuss the results with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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