Kelly Qian Lin Tan¹, Shan Wei Huang¹, Kwai Peng Chan^1,2, Cecilia Cheng Lai Ngan^1,2

¹Department of Microbiology, Singapore General Hospital, Singapore; ²Singhealth Duke-NUS Pathology Academic Clinical Programme, Singapore

Introduction: The BioSystems Slide Test Kit (BioSystems) kit was evaluated with a view to replace the currently-used Biokit Rheumajet ASO (Rheumajet) kit for the testing of anti-streptolysin O antibodies (ASO) in sera.

Aim: To determine the percentage agreements of BioSystems to Rheumajet for adults as well as children <7 years old (yo); and to look for prozone effects on samples with high titres in BioSystems.

Method: BioSystems was evaluated using 10 proficiency testing (PT) samples from CAP ASO PT Program. Additionally, 74 clinical samples were tested to calculate the percentage agreement between Rheumajet and BioSystems. Of the 74 samples, 45 were from children <7 yo with titres at 100 IU/mL; 10 were negative samples and the rest were positive at varying titres.

Results: Prozone phenomenon was not detected in samples with high titres (800-6,400). The positive percentage agreement (PA) for samples from children <7 yo was 91.1%. Total positive PA was 93.6%; negative PA was 100%. Total PA was 100% and 94.5% for PT and clinical samples respectively.

Conclusion: BioSystems yielded satisfactory results using PT and clinical samples and was suitable for the detection of ASO for adult and children samples.

Author Contributions: Conceptualization: Cecilia CL Ngan & Shan Wei Huang; Methodology and Investigation: Cecilia CL Ngan & Shan Wei Huang; Writing and original: Kelly Qian Lin Tan; Review & Editing: Cecilia CL Ngan, Shan Wei Huang and Kwai Peng Chan