Comparison of two automated immunoassays for quantifying ProGRP, SCC and HE4 in serum: impact on diagnostic accuracy

ProGRP (Progastrin-releasing peptide), SCC (Squamous Cell Carcinoma Antigen), and HE4 (Human epididymis protein 4) are serum tumor markers (STMs) frequently used in clinical practice, particularly for detection and monitoring of ovarian and lung neoplasms. In clinical laboratories, their quantification is commonly performed using automated immunoassays. Nevertheless, variations in results obtained by different immunoassays can impact diagnostic accuracy and effectiveness of patient monitoring. Our aim is to assess differences in STMs concentrations between two automated immunoassays: the Elecsys (Roche) and the Architect (Abbott), which are integrated into the Cobas e402 and Architect i2000SR systems respectively. We included 401 serum samples from patients with different clinical conditions: patients with cancer (n = 170), benign diseases (n = 100) and a control group (n = 131). ProGRP, SCC, and HE4 concentrations were quantified in parallel by both analyzers. To evaluate the clinical impact of changing these methodologies, overall concordance, the kappa index and ROC (Receiver Operating Characteristic) curves were calculated. While some discrepancies were noted in specific cases, overall, we obtained a good correlation for three STMs, with a Pearson coefficient for proGRP (r = 0.99), SCC (r = 0.95) and HE4 (r = 0.973). We also obtained a similar performance in the differential diagnosis of cancer, according to the results of the ROC analyses for Cobas and Archictect assays respectively: proGRP (AUC = 0.92; 0.91), SCC (AUC = 0.90; 0.92) and HE4 (AUC = 0.92; 0.93).