Establishment of the magnetic separation enzyme immunofluorescence method for detecting insulin

AIM To establish a convenient and sensitive magnetic separation enzyme immunofluorescence (MEIF) method for detecting human insulin. METHODS Two monoclonal antibodies (mAbs) were conjugated with FITC and alkaline phosphatase (AP) respectively, which were incorporated magnetic solid phase separation. Magnetic beads were coupled with sheep anti-FITC antibody as solid phase and 4-Methylumbelliferyl-phosphoric acid (4-MUP) was used as substrate to set up MElF for detecting insulin. RESULTS The sensitivity of this assay was 2.0 microIu/mL, the linear range was from 0 microIu/mL to 188.52 microIu/mL, and the intra-assay variation and inter-assay variation were 4.3%-5.2% and 2.6%-9.5%, respectively. The recovery rate of dilution was 92.6%-117% and the recovery rate of accession was 106%-121%.The result of the assay correlated well with that of magnetic enzyme chemiluminescence immunoassay system. CONCLUSION The MEIF for detecting insulin is low at cost, sensitive, specific and stable, which can be widely used in clinical immune detection.