streptolysin O (ASO) Ab titer
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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
More general terms
Additional terms
References
- ↑ Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
- ↑ Jump up to: 2.0 2.1 Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
- ↑ Streptolysin O Antibody Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0050095.jsp