Anti-Deoxyribonucleic B are a quantitative blood test measures the presence of serologic antibodies collected from patient’s blood having recent group A streptococcus bacterial infection, Streptococcus pyogenes. In a patient with suspected post-streptococcal glomerulonephritis, anti-streptolysin-O titres can be negative even after strep pharyngitis. Some studies suggest that up to 85% of patients with acute rheumatic fever from group A strep infection will be positive for ASO titers, leaving 15% of patients having been diagnosed with rheumatic fever negative for ASO titers. In addition, and contrary to percentages seen in strep pharyngitis, strep skin infection induces ASO antibodies less often, which can be problematic for physicians searching for a cause of the glomerulonephritis and having a high suspicion that its etiology was strep.