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streptolysin O (ASO) Ab titer

Reference interval: - negative is < 150 Todd units [2] Clinical significance: - antibody titer against streptolysin O produced by Group A beta hemolytic Streptococci - titers rise 1 week after infection, peak in 3-5 weeks & return to baseline in 6 months to 1 year - a rise in titer of at least 4-fold over a 1-2 week period is more useful than a single determination Increases: - 40-50% of patients with group A beta hemolytic streptococcal pharyngitis (culture proven) - 80-85% of patients with rheumatic fever show a rise in ASO titer - 25% of streptococcal pyoderma Interferences: - serum beta lipoprotein in liver disease & some bacterial proteins may neutralize the hemolytic properties of streptolysin O thus producing a false positive titer

Related

group A beta-hemolytic streptococcus

General

streptolysin O (ASO) Ab in serum

References

  1. Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
  3. Streptolysin O Antibody Laboratory Test Directory ARUP: 50095