An ASO Test is suggested for detecting a strep infection. This diagnostic tool is considered effective in diagnosing the condition, and creating the subsequent treatment plan.

What is an ASO Test?

The antistreptolysin O (ASO) titer test is a type of blood test, which is performed specifically for detecting strep infections. It does it by measuring the antibodies created by the body in response to a toxic called streptolysin O. The group A Streptococcus (GAS) bacteria cause the body to produce these bacteria. If an individual has a strep infection that is caused by GAS bacteria, the body will naturally produce antistreptolysin O antibodies.

In the case of strep throat, antibiotics are suggested to help kill the bacteria and eliminate it. But, sometimes, a strep infection does not show any symptoms, causing a delay in the treatment. This can trigger complications in the future. With the help of an ASO titer test, the doctor can determine if the patient has experienced a strep infection recently or if antistreptolysin antibodies are present in the blood. 

When Should You Get the ASO Test Done?

Doctors typically suggest an ASO test if the patient is experiencing symptoms of post-streptococcal complications such as bacterial endocarditis, glomerulonephritis, and rheumatic fever. It takes the body 3 to 8 weeks for antistreptolysin antibodies to reach the highest levels after a strep infection. By examining the antibody levels, the doctor can determine if the symptoms the patient is experiencing can be attributed to post-streptococcal complications.

Procedure for ASO test

For an ASO Titer test, collecting a blood sample is necessary. The blood test is done by a lab technician as they are skilled in obtaining a blood sample. The blood is drawn from a vein located in either the inner arm or hand. A needle is gently inserted into the vein to draw a sample of the blood, which is then collected in a special tube designed for this purpose. After drawing the blood sample for ASO test, the tube containing the blood sample is carefully dispatched to a laboratory for a comprehensive analysis.

After the analysis is done, the doctor or the patient receives the results. On the basis of the outcomes of the test, the healthcare provider shares insights into the medical condition and guides the patient on any necessary further steps or treatments. This process ensures that the patient has complete knowledge of his/her health and what they should expect afterwards. 

How to Prepare for the ASO Test?

The healthcare provider will provide specific instructions regarding any necessary preparations for the ASO titer test. The patients may be advised to avoid consuming food or beverages for a period of six hours before undergoing the test. In addition, the doctor might suggest avoiding the use of certain medications before the ASO test. It is important to inform the doctor about the medications being taken at the time of the test including both over-the-counter and prescription medications. 

Any other information regarding lifestyle changes, suggested by the doctor must also be followed by the patient to ensure optimal treatment outcomes and minimum complications. 

Values of ASO Test Results

Understanding ASO test results is integral for the patients as well to be able to comprehend the results. It's important to note that the result ranges can vary among different diagnostic labs. A normal ASO test reading falls below 200. However, in children under 5 years old, it should be under 100. If the test results show an elevated ASO value, it may hint towards the presence of a post-streptococcal complication.

Sometimes, to confirm the results, the doctor might opt to repeat the test within a span of 10 to 14 days as ASO antibodies typically appear within a week after the onset of the infection. If both tests return negative results, it suggests that a Streptococcus infection does not cause the symptoms. In such cases, the doctor may further run other tests to check for the cause of the symptoms. 

If the test result shows elevated levels of ASO antibodies, it may be an indication of a recent infection. On the other hand, low antibody levels suggest that the infection is improving. 

How to Control High ASO Titer

If the reports reveal elevated ASO titer levels, the patient is required to take measures to bring it down to the normal level. Here’s what can be done to control high ASO titer levels: 

• Consult a healthcare provider to confirm if  a streptococcal infection is present.
• Take the medication suggested by the doctor as prescribed and without fail. 
• The course of antibiotics must be completed. 
• Over-the-counter medications can be used to manage the symptoms if needed.
• Take complete rest to let the body recover from the infection.
• Drink ample water and keep hydrated to promote recovery.
• Follow up with the doctor for further tests and care as necessary.

FAQs

1. What does "ASO positive" mean?

"ASO positive" refers to a positive result on the Antistreptolysin O (ASO) titer test. This indicates elevated levels of ASO antibodies in the blood, which means a recent or current infection with Group A Streptococcus (GAS) bacteria. This bacteria can lead to various illnesses, including strep throat and other streptococcal infections.

2. Can ASO be used to diagnose strep throat?

Typically, an ASO titer is not used as the primary method for diagnosing strep throat. A strep throat is commonly diagnosed by employing a rapid strep test, also known as a throat swab or throat culture. These tests help detect the presence of GAS bacteria in the throat. The ASO titer test is considered pretty useful for identifying past streptococcal infections or assessing the risk of post-streptococcal complications.

3. Does ASO positive mean arthritis?

The purpose of an ASO test is to measure the presence of antibodies (ASO antibodies) produced by the body in response to a streptococcal infection, and may not necessarily indicate arthritis. But, it should be noted that untreated streptococcal infections, especially those that lead to rheumatic fever, can cause joint inflammation and rheumatoid arthritis. But, an ASO positive result alone does not directly imply that a patient has arthritis.