Multiplexed quantification of insulin and C-peptide by LC-MS/MS without the use of antibodies.
J Mass Spectrom Adv Clin Lab
; 25: 19-26, 2022 Aug.
Article
em En
| MEDLINE
| ID: mdl-35734440
ABSTRACT
Introduction:
The measurement of insulin and C-peptide provides a valuable tool for the clinical evaluation of hypoglycemia. In research, these biomarkers are used together to better understand hyperinsulinemia, hepatic insulin clearance, and beta cell function. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is an attractive approach for the analysis of insulin and C-peptide because the platform is specific, can avoid certain limitations of immunoassays, and can be multiplexed. Previously described LC-MS/MS methods for the simultaneous quantification of insulin and C-peptide measure the intact analytes and most have relied on immunoaffinity enrichment. These approaches can be limited in terms of sensitivity and interference from auto-antibodies, respectively. We have developed a novel method that does not require antibodies and uses proteolytic digestion to yield readily ionizable proteotypic peptides that enables the sensitive, specific, and simultaneous quantitation of insulin and C-peptide.Methods:
Serum samples were precipitated with acetonitrile. Analytes were enriched using solid phase extraction and then digested with endoproteinase Glu-C. Surrogate peptides for insulin and C-peptide were analyzed using targeted LC-MS/MS.Results:
Inter-day imprecision was below 20 %CV and linearity was observed down to the lower limit of quantitation for both analytes (insulin = 0.09 ng/mL, C-peptide = 0.06 ng/mL). Comparison to a commercially available insulin immunoassay (Beckman Coulter UniCel DxI 600 Access) revealed a 30% bias between methods.Conclusion:
A novel LC-MS/MS method for the simultaneous analysis of insulin and C-peptide using Glu-C digestion was developed and evaluated. A detailed standard operating procedure is provided to help facilitate implementation in other laboratories.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Mass Spectrom Adv Clin Lab
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Estados Unidos