Streptococcal Antibody Tests

Risks :

The risks associated with these tests are minimal, but may include slight bleeding from the blood-drawing site, fainting or feeling lightheaded after the blood is drawn, or blood accumulating under the puncture site (hematoma).

Normal Results:

Antistreptolysin O titer:

• adult: 160 Todd units/ml
• child: six months to two years: 50 Todd units/ml; two to four years: 160 Todd units/ml; five to 12 years: 170-330 Todd units/ml
• newborn: similar to the mother's value

Antideoxyribonuclease-B titer:

• adult: 85 units
• child (preschool): 60 units
• child (school age): 170 units

Streptozyme: less than 100 streptozyme units.

Abnormal Results:

Antistreptolysin O titer: Increased levels are seen after the second week of an untreated infection in acute streptococcal infection, and are also increased with acute rheumatic fever, acute glomerulonephritis (66% of patients will not have high ASO titers), and scarlet fever.

Antideoxyribonuclease-B titer: Increased titers are seen in cases of acute rheumatic fever and post-streptococcal glomerulonephritis.

Streptozyme: As this is a screening test for antibodies to streptococcal antigens, increased levels require more definitive tests to confirm diagnosis.