Evaluation of a new latex agglutination test for detection of streptococcal antibodies

A liposome-enhanced latex agglutination test (Leapstrep, Cooper Biomedical, Inc., Malvern, PA) was evaluated for its efficacy as a screening test for antistreptolysin O (ASO) and antideoxyribonuclease B (ADNB) antibodies. A total of 179 sera were tested by both Leapstrep and reference ASO and ADNB test methods. The Leapstrep test had a sensitivity of 77% and a specificity of 69% for ASO antibodies when compared to a microtiter adaptation of the Todd-Hewitt ASO tube test. It had a sensitivity of 76% and 75% specificity for ADNB antibodies as compared to the ADNB microtiter enzyme neutralization test. The overall sensitivity of Leapstrep for detecting ASO and/or ADNB antibodies was 73%. The Leapstrep test failed to detect elevated levels of ASO and/or ADNB antibodies in eight patients with streptococcal infections or poststreptococcal sequelae. The Leapstrep test appears to have insufficient sensitivity to be recommended as a screening test for streptococcal antibodies.