20/11/2025
A*O is a blood test that measures the level of antibodies produced against Streptolysin-O, a toxin released by Group A Streptococcus bacteria.
It helps diagnose complications that occur after a Streptococcal infection, such as:
Rheumatic fever ❤️
Glomerulonephritis (kidney inflammation) 🩺
Scarlet fever
Post-streptococcal arthritis
📈 Normal A*O Levels
Adults: < 200 IU/mL
Children: < 400 IU/mL