Development and analytical performance of a new ARCHITECT automated dipeptidyl peptidase-4 immunoassay

Pract Lab Med. 2017 Oct 20;9:58-68. doi: 10.1016/j.plabm.2017.10.003. eCollection 2017 Dec.


Background: Dipeptidyl peptidase-4 (DPP-4) may be a suitable biomarker to identify people with severe asthma who have greater activation of the interleukin-13 (IL-13) pathway and may therefore benefit from IL-13-targeted treatments. We report the analytical performance of an Investigational Use Only immunoassay and provide data on the biological range of DPP-4 concentrations.

Methods: We assessed assay performance, utilising analyses of precision, linearity and sensitivity; interference from common endogenous assay interferents, and from asthma and anti-diabetic medications, were also assessed. The assay was used to measure the range of serum DPP-4 concentrations in healthy volunteers and subjects with diabetes and severe, uncontrolled asthma.

Results: The total precision of DPP-4 concentration measurement (determined using percentage coefficient of variation) was ≤5% over 20 days. Dilution analysis yielded linear results from 30 to 1305 ng/mL; the limit of quantitation was 19.2 ng/mL. No notable endogenous or drug interferences were observed at the expected therapeutic concentration. Median DPP-4 concentrations in healthy volunteers and subjects with asthma or Type 1 diabetes were assessed, with concentrations remaining similar in subjects with diabetes and asthma across different demographics.

Conclusion: These analyses indicate that the ARCHITECT DPP-4 Immunoassay is a reliable and robust method for measuring serum DPP-4 concentration.

Keywords: Asthma; Automated immunoassay; BGG, bovine gamma globulin; BMI, body mass index; Biomarker; CI, confidence interval; CLSI, Clinical Laboratory Standards Institute; CV, coefficient of variation; DPP-4, dipeptidyl peptidase-4; Dipeptidyl peptidase-4; HAMA, human anti-mouse antibodies; IL-13; IL-13, interleukin-13; IUO, Investigational Use Only; Ig, immunoglobulin; LoB, Limit of Blank; LoD, Limit of Detection; LoQ, Limit of Quantitation; PI, prediction interval; RF, rheumatoid factor; RLU, relative light units; SRT, serum tube-red top; SST, serum separator tube; Th2, T-helper-2; mAb, monoclonal antibody.