Alternative antibody for the detection of CA19-9 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access® GI Monitor assay on the UniCel® DxI 800 Immunoassay System

Abstract

Background: Gastrointestinal cancer antigen CA19-9 is known as a valuable marker for the management of patients with pancreatic cancer. Methods: The analytical and clinical performance of the Access ᮋ GI Monitor assay (Beckman Coulter) was evaluated on the UniCel ᮋ DxI 800 Immunoassay System at five different European sites and compared with a reference method, defined as CA19-9 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the GI Monitor ranged between 3.4% and 7.7%, and inter-laboratory reproducibility between 3.6% and 4.0%. Linearity upon dilution showed a mean recovery of 97.4% (SDq7.2%). Endogenous interferents had no influence on GI Monitor levels (mean recoveries: hemoglobin 103%, bilirubin 106%, triglycerides 106%). There was no high-dose hook effect up to 115,000 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access ᮋ GI Monitor and Elecsys CA19-9 (Rs0.959, slopes1.004, interceptsq0.17). GI Monitor serum levels were low in healthy individuals (ns267, medians6.0 kU/L, 95th percentiles23.1 kU/L), higher

Clinical Performance of CEA, CA19-9, CA15-3, CA125 and AFP in Gastrointestinal Cancer Using LOCI™-based Assays

“…We showed that in pancreatic and gallbladder cancer, best diagnostic power was achieved by CA19-9, with an AUC of 0.85 and a sensitivity of 60.6% at a 95% specificity versus benign gastrointestinal diseases. These results are in line with earlier study on pancreatic cancer that described AUCs of 0.827 (sensitivity of 53.2% at 95% specificity) and 0.850 (sensitivity of 58.1% at 95% specificity) when comparing them with benign gastrointestinal diseases using the Access™ GI Monitor and the Elecsys™ CA19-9 (22). In colorectal cancer, best performance was achieved by CEA with an AUC of 0.84 and a sensitivity of 51.7% at 95% specificity versus benign gastrointestinal diseases.…”

“…For cardiac troponin I, an acceptable analytical performance of the LOCI™ method on the Dimension EXL (Siemens Healthcare Diagnostics) was found (21). The evaluation of the analytical performance of CA19-9 using non LOCI™-based immunoassays revealed minimal differences in slopes and intercepts when comparing two different immunoassays; good correlation was shown for all patients in their collective (22). In addition, for CA15-3 the analytical performance was accurate but not optimal and a difference in slope of 20-40% lower concentrations for the applied method was detected (23).…”

Application of a Time-Varying Covariate Model to the Analysis of CA 19-9 as Serum Biomarker in Patients with Advanced Pancreatic Cancer

“…Of note, all CA 19-9 measurements in this study were conducted with the use of one defined assay (Elecsys), thus ruling out an assay-dependent analytic bias (8,21). In addition, we did not categorize CA 19-9, but modeled CA 19-9 as a continuous covariate where we found the logarithmic transformation of CA 19-9 as an adequate one to model the nonlinear relationship between CA 19-9 and the corresponding hazard.…”

Method Comparison for Ca 15-3, Ca 19-9, and Ca 125 Determination Using the New Loci Technique of Dimension Vista 1500 and Immulite 2000 Xpi

“…[17][18][19] Lastly, correlations of the biomarker development in the course of specific cancer therapies with the therapeutic outcome and=or disease progression are important points to consider in clinical marker validation before introduction of a new method into clinical routine.…”

“…In particular, this comparison reveals the higher value scatter in the lower measuring range that is often observed in method comparison studies. [17][18][19] Possibly, this can be attributed to different antibody affinities resulting in discrepant values particularly when small amounts of antigens are present. Other studies compared each Vista marker with different methods and only over the entire measurement range.…”