Antistreptolysin-O (ASL-O)

Why this test?

To determine a recent infection with streptococcus A group. Most often, this infection has a characteristic clinical picture, so it is easy to recognize.

Streptococcus is treated with antibiotics, and as a result, the microbe is destroyed. When the infection proceeds atypically, is not treated (or treated ineffectively), the risk of post-streptococcal complications - rheumatic fever and glomerulonephritis - increases.

Thus, the analysis for ASL-O is necessary to confirm the connection of the symptoms of these diseases with streptococcal infection. To assess the effectiveness of treatment, as the concentration of ASL-O in the patient's blood decreases during recovery.

 In what cases is it prescribed?

When there is a reason to believe that the symptoms are caused by a previous streptococcal infection.

The testing is conducted when complaints appear, usually 2-3 weeks after angina or streptococcal skin damage.

The importance of the analysis increases if it is prescribed several times with an interval of 10-14 days - in this case, a change in the antibody titer (increase or decrease) can be assessed. 1-2 weeks after starting treatment for rheumatic fever or glomerulonephritis (to assess the effectiveness of treatment).

 Test information

Antistreptolysin O (ASL O) is an antibody produced by the body directed against streptolysin O, a toxic enzyme secreted by some groups of hemolytic streptococcus. Betahemolytic streptococcus group A (Streptococcus pyogenes) is a bacterium that causes strep throat, scarlet fever, strep throat, and skin infection. In most cases, streptococcal infection has a characteristic clinical picture, is recognized and treated with antibiotics, as a result of which the microbe is destroyed.

If the infection proceeds atypically, which cannot be treated or is treated ineffectively, the risk of post-streptococcal complications - rheumatic fever and glomerulonephritis - increases. This usually happens in children after angina or scarlet fever.

Such complications of streptococcal infection are not frequent, but they should be remembered. Rheumatic fever can be manifested by an increase in temperature, redness of the skin around the joints and their swelling, pain in the heart, shortness of breath, fatigue, and glomerulonephritis - fever, pain in the lower back, a decrease in the amount of urine and its redness.

Rheumatic fever leads to the development of heart defects, glomerulonephritis - to kidney failure and increased blood pressure. Since the symptoms of this disease can be accompanied by other conditions, the antistreptolysin O test allows you to find out whether they are caused by a streptococcal infection. The level of ASL O increases a week after infection, reaches a maximum after 3-6 weeks and decreases after six months to a year.