Clinical Utility and Cross-Reactivity of Insulin and C-Peptide Assays by the Lumipulse G1200 System

BACKGROUND: Measurement of insulin and C-peptide concentrations is important for deciding whether insulin treatment is required in diabetic patients. We aimed to investigate the analytical performance of insulin and C-peptide assays using the Lumipulse G1200 system (Fujirebio Inc., Tokyo, Japan). METHODS: We examined the precision, linearity, and cross-reactivity of insulin and C-peptide using five insulin analogues and purified proinsulin. A method comparison was conducted between the Lumipulse G1200 and Roche E170 (Roche Diagnostics, Mannheim, Germany) systems in 200 diabetic patients on insulin treatment. Reference intervals for insulin and C-peptide concentrations were determined in 279 healthy individuals. RESULTS: For insulin and C-peptide assays, within-laboratory precision (% CV) was 3.78–4.14 and 2.89–3.35%, respectively. The linearity of the insulin assay in the range of 0–2,778 pmol/L was R2=0.9997, and that of the C-peptide assay in the range of 0–10 nmol/L was R2=0.9996. The correlation coefficient (r) between the Roche E170 and Lumipulse G1200 results was 0.943 (P < 0.001) for insulin and 0.996 (P < 0.001) for C-peptide. The mean differences in insulin and C-peptide between Lumipulse G1200 and the Roche E170 were 19.4 pmol/L and 0.2 nmol/L, respectively. None of the insulin analogues or proinsulin showed significant cross-reactivity with the Lumipulse G1200. Reference intervals of insulin and C-peptide were 7.64–70.14 pmol/L and 0.17–0.85 nmol/L, respectively. CONCLUSIONS: Insulin and C-peptide tests on the Lumipulse G1200 show adequate analytical performance and are expected to be acceptable for use in clinical areas.

Evaluation of the Performance of Lumipulse G1200 for Tumor Marker Assays

BACKGROUND: Tumor markers are used for diagnosing cancers and monitoring responses to cancer therapy. In this study, we evaluated the performance of Lumipulse G1200 (Fujirebio, Japan), a fully automated serum analyzer, for immunoassays of tumor markers. METHODS: We determined the precision and linearity of assays performed using Lumipulse G1200 and the correlation between the results of this and other analyzers used for tumor markers according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). We used 9 tumor markers, namely, carcinoembryonic antigen, alpha-fetoprotein, cancer antigen 125, cancer antigen 15-3 (CA 15-3), cancer antigen 19-9, prostate specific antigen, protein induced by vitamin K absence or antagonist-II, and pepsinogens I and II. Further, we validated reference intervals using 20 serum samples of healthy individuals. RESULTS: Lumipulse G1200 yielded acceptable precision with total CV0.975 for all markers, except pepsinogen I (0.9569). The reference intervals provided by the manufacturer met the criteria mentioned in the CLSI guideline. CONCLUSIONS: Assays using Lumipulse G1200 had high precision, clinically acceptable linearity, and good correlation with the established assays. This indicates that Lumipulse G1200 can be potentially used in routine laboratories.

Evaluation of the Performance of Lumipulse G1200 for Tumor Marker Assays

BACKGROUND: Tumor markers are used for diagnosing cancers and monitoring responses to cancer therapy. In this study, we evaluated the performance of Lumipulse G1200 (Fujirebio, Japan), a fully automated serum analyzer, for immunoassays of tumor markers. METHODS: We determined the precision and linearity of assays performed using Lumipulse G1200 and the correlation between the results of this and other analyzers used for tumor markers according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). We used 9 tumor markers, namely, carcinoembryonic antigen, alpha-fetoprotein, cancer antigen 125, cancer antigen 15-3 (CA 15-3), cancer antigen 19-9, prostate specific antigen, protein induced by vitamin K absence or antagonist-II, and pepsinogens I and II. Further, we validated reference intervals using 20 serum samples of healthy individuals. RESULTS: Lumipulse G1200 yielded acceptable precision with total CV0.975 for all markers, except pepsinogen I (0.9569). The reference intervals provided by the manufacturer met the criteria mentioned in the CLSI guideline. CONCLUSIONS: Assays using Lumipulse G1200 had high precision, clinically acceptable linearity, and good correlation with the established assays. This indicates that Lumipulse G1200 can be potentially used in routine laboratories.