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Moradian A, Goonatilleke E, Lin TT, Hatten-Beck M, Emrick M, Schepmoes AA, Fillmore TL, MacCoss MJ, Sechi S, Sobhani K, Little R, Kabytaev K, van Eyk JE, Qian WJ, Hoofnagle AN. Interlaboratory Comparison of Antibody-Free LC-MS/MS Measurements of C-peptide and Insulin. Clin Chem 2024; 70:855-864. [PMID: 38549041 DOI: 10.1093/clinchem/hvae034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/29/2024] [Indexed: 05/01/2024]
Abstract
BACKGROUND The enhanced precision and selectivity of liquid chromatography-tandem mass spectrometry (LC-MS/MS) makes it an attractive alternative to certain clinical immunoassays. Easily transferrable work flows could help facilitate harmonization and ensure high-quality patient care. We aimed to evaluate the interlaboratory comparability of antibody-free multiplexed insulin and C-peptide LC-MS/MS measurements. METHODS The laboratories that comprise the Targeted Mass Spectrometry Assays for Diabetes and Obesity Research (TaMADOR) consortium verified the performance of a validated peptide-based assay (reproducibility, linearity, and lower limit of the measuring interval [LLMI]). An interlaboratory comparison study was then performed using shared calibrators, de-identified leftover laboratory samples, and reference materials. RESULTS During verification, the measurements were precise (2.7% to 3.7%CV), linear (4 to 15 ng/mL for C-peptide and 2 to 14 ng/mL for insulin), and sensitive (LLMI of 0.04 to 0.10 ng/mL for C-peptide and 0.03 ng/mL for insulin). Median imprecision across the 3 laboratories was 13.4% (inter-quartile range [IQR] 11.6%) for C-peptide and 22.2% (IQR 20.9%) for insulin using individual measurements, and 10.8% (IQR 8.7%) and 15.3% (IQR 14.9%) for C-peptide and insulin, respectively, when replicate measurements were averaged. Method comparison with the University of Missouri reference method for C-peptide demonstrated a robust linear correlation with a slope of 1.044 and r2 = 0.99. CONCLUSIONS Our results suggest that combined LC-MS/MS measurements of C-peptide and insulin are robust and adaptable and that standardization with a reference measurement procedure could allow accurate and precise measurements across sites, which could be important to diabetes research and help patient care in the future.
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Affiliation(s)
- Annie Moradian
- Precision Biomarker Laboratories, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Elisha Goonatilleke
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
| | - Tai-Tu Lin
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Maya Hatten-Beck
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
| | - Michelle Emrick
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
| | - Athena A Schepmoes
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Thomas L Fillmore
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, WA, United States
| | - Salvatore Sechi
- Division of Diabetes, Endocrinology, & Metabolic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Kimia Sobhani
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Randie Little
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
| | - Kuanysh Kabytaev
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
| | - Jennifer E van Eyk
- Precision Biomarker Laboratories, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Advanced Clinical Biosystems Research Institute, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Wei-Jun Qian
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Andrew N Hoofnagle
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
- Department of Medicine, Kidney Research Institute, University of Washington, Seattle, WA, United States
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