The serotyping results of the Quellung reaction was compared with the newly developed multiplex latex assay and the sensitivity of the Quellung reaction was compared.

We checked the serotypes of 35 samples obtained from patients treated at Yonsei University Medical Center using the multiplex latex bead method and compared the results with the serotypes previously obtained via the Quellung reaction.

A decrease in the mean fluorescence was detected in the samples tested with the multiplex assay. Seventeen samples out of the 27 samples agreed to the results of the Quellung assay. We were only able to confirm the concordance of 11 serotypes out of 14 serotypes available.

The Quellung reaction is time consuming procedure and prone to errors even with expertise in the procedure, and other alternate methods in serotyping have been investigated to overcome these problems. The newly developed multiplex latex bead assay can test more samples at the same time and has a higher degree of sensitivity. A large scale trial is required to test the sensitivity of the new assay across various serotypes along with efforts to increase the sensitivity of the Quellung assay. The preliminary data suggests that this method may be widely used.