Antistreptolysin O titer

Antistreptolysin O Titer Test

The Antistreptolysin O (ASO) titer test is used to detect the presence and level of antibodies against streptolysin O, a bacterial toxin. The test is used to help diagnose a past or present streptococcal infection, and it can show whether or not treatment for the infection has been effective.


No special preparation is necessary for the ASO titer test. The procedure involves taking a blood sample, typically from the arm. If the sample is to be taken from a vein, an elastic band tied around the arm may used to increase the flow of blood.


The ASO titer is performed by drawing a sample of blood from the patient's arm and testing it for the presence and quantity of anti-streptolysin O antibodies. The sample is usually analyzed in a laboratory, and results are typically available in a few days.


The ASO titer test can be used to detect both primary and secondary forms of streptococcal infection. Primary infections are caused by direct exposure to the bacteria, while secondary infections occur when antibodies produced to fight the bacteria are not completely successful. The test can also be used to monitor the efficacy of antibiotic treatments.


In general, the risks associated with an ASO titer test are minimal. Like any blood draw procedure, there is a minor risk of infection or bleeding at the site of the puncture. In rare cases, an allergic reaction to the needle or anticoagulant may occur.

Why Is the Test Performed?

The ASO titer test is primarily used to help diagnose a streptococcal infection or monitor the effectiveness of antibiotic treatment. The test can also be used to evaluate the risk of a recurrent streptococcal infection. Additionally, it may be used to help diagnose rheumatic fever or rheumatic heart disease.

When Is the Test Performed?

The ASO titer test is usually recommended when a person exhibits symptoms of a streptococcal infection, such as fever, sore throat, or pneumonia. It may also be performed if a person has been exposed to streptococcal bacteria, or if they have a history of recurrent infection. In some cases, the test may be done as part of regular check-up.