Anti-DNase B (antideoxyribonuclease-B, ADN B) and ASO are the main antibodies produced by the body in response to a group A beta-hemolytic streptococcus infection (strep A). This bacteria is responsible for many throat infections, impetigo and cellulitis and usually responds well to antibiotic treatment. If a strep A infection is not diagnosed or is poorly treated, it can lead to complications such as acute rheumatism (rheumatic fever) or glomerulonephritis (kidney inflammation). However, a small percentage of people who develop complications and have low ASO levels may have high levels of anti-DNase B. This is especially the case when the glomerulonephritis is linked to a strep A skin infection.
A negative or very low result, especially if repeated 10 to 14 days later, indicates that the person probably did not have a recent strep A infection, but there are rare exceptions. If the concentration is high or increasing, a recent strep A infection is very likely. The anti-DNase B blood test cannot be used to predict whether complications will occur or to predict the type and severity of the disease. If symptoms of rheumatic fever or glomerulonephritis are present, a high anti-DNase B titre will help confirm the diagnosis.