SP-PLA was used to detect Aβ protofibrils in larger sample volumes. Aβ protofibrils were spiked in 0.8 ml buffer and detected by SP-PLA. The result for SP-PLA is compared to standard mAb158 ELISA. The left Y-axis shows cycle threshold values for real-time PCR after SP-PLA, while the right Y-axis shows the OD A450nm for ELISA. The X-axis shows concentrations of Aβ protofibrils in pg/ml. Error bars indicate standard deviations from the mean for triplicates for each reaction.