Table 3.
Characteristics of current human proinsulin and C-peptide assays
| Propeptide cross-reactivity | Mature peptide cross-reactivity | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Manufacturer | Catalog number | Sensitivity | Intact proinsulina | split-32,33 | des-31,32 | split-65,66 | des-64,65 | Mature insulin | C-peptidea |
| Proinsulin | |||||||||
| Abcam | ab242235 | 0.75 pmol/L | - | NS | NS | NS | NS | >50 ng/mL | >50 ng/mL |
| Alpco | 80-PINHUT-CH01 | 0.455 pg/mL | - | NS | 100% | NS | 100% | <0.6% | <0.1% |
| EMD Millipore | EZHPI-15K | 0.5 pmol/L | - | NS | 100% | NS | 81% | >200 µU/mL | >10 ng/mL |
| Invitron | IV2-002 | 0.02 pmol/L | - | 5.6% | 1.4% | 37% | 63% | 0% | 0% |
| Mercodia | 10-1118-01 | 1.7 pmol/L | - | 95% | 95% | 90% | 84% | <0.03% | <0.006% |
| Meso Scale Diagnostics | K1516MK | 0.05 pmol/L | - | NS | NS | NS | NS | <0.5% | 0.7% |
| R&D Systems | DPINS0 | 1.43 pmol/L | - | NS | NS | NS | NS | >3450 pmol/L | NS |
| TECOmedical Group | TE1012 | 0.3 pmol/L | - | 5000 pmol/L | <200 pmol/L | 1000 pmol/L | 200 pmol/L | <10 000 pmol/L | 50 000 pmol/L |
| C-peptide | |||||||||
| Alpco | 80-CPTHU-CH01 | <4.32 pg/mL | <0.01% | NS | 0.3% | NS | 33.2% | ND | - |
| Alpco | 80-CPTHU-E01.1 | 2.95 pmol/L | 3% | NS | NS | NS | NS | <0.01% | - |
| Beckman Coulterb | C33451 | 0.01 ng/mL | 3% | NS | NS | NS | NS | 0% | - |
| Invitron | IV2-004 | 5 pmol/L | 2% | NS | NS | NS | NS | 0% | - |
| Mercodia | 10-1136-01 | ≤25 pmol/L (0.076 μg/L) | 2% | 2% | 3% | 10% | 74% | <0.0006% | - |
| Mercodia | 10-1141-01 | 2.5 pmol/L (0.0076 µg/L) | 5% | 2% | 3% | 10% | 74% | <0.0006% | - |
| Meso Scale Diagnostics | K1516JK | 14 pg/mL | 27% | ND | ND | ND | ND | 0.50% | - |
| Meso Scale Diagnostics | K151X5D | 4.72 pg/mL | 32.4% | NS | NS | NS | NS | 0.03% | - |
| Tosoh | 25284 | 0.2 ng/mL | 31.5% | NS | NS | NS | NS | ND | - |
Information provided is as stated by the manufacturers and not independently verified. Stated information was accessed from manufacturer websites and supporting technical documents during the period February 10, 2021 to March 7, 2021.
Cross-reactivity values reported as percentages represent (100%) (detected proinsulin concentration)/(non-target analyte concentration tested).
Cross-reactivity values reported as concentrations represent the minimum required concentration of non-target analyte to be detected by the ELISA.
Abbreviations: ND, not detected; NS, not stated.
aIn the case of proinsulin assays, it is assumed to be 100% and for C-peptide assays similarly it is assumed to be 100%
bRadioimmunoassay