Proximity Extension Assay (PEA) technology

Overcoming the specificity issues of multiplexed immunoassays

Each of the 96 oligonucleotide antibody-pairs contains unique DNA sequences allowing hybridization only to each other. Subsequent proximity extension will create 96 unique DNA reporter sequences which are amplified by real-time PCR. A limiting factor of multiplexed immunoassays is the antibody cross-reactivity which restricts the degree of multiplexing of most assays to below 10-plex. Cross-reactive events will not be detected with Olink’s panels since only matched DNA reporter pairs can hybridize to produce an amplicon for NGS or real-time qPCR. This allows for scalable multiplexing without loss of specificity and sensitivity (see figures below).

A) Conventional immunoassays: cross-reactivity due to unspecific binding of antibodies limits the degree of multiplexing.

B) Olink’s technology: unique DNA oligo sequences report only matched DNA-pairs (e.g. 1A+1B). Cross-reactive events are not detected.