Determinazione della progranulina con un nuovo metodo automatizzato

Background: Progranulin (PGRN) is a glycoprotein coded by the GRN gene, on the chromosome 17q21. GRN mutations are responsible for 22% of familial cases of frontotemporal dementia (FTD). Until now, plasma PGRN measurement was performed using a traditional manual ELISA method (Mediagnost, Reutlingen, Germany) that provides, in our experience, relevant clinical information. The aim of the study was to evaluate the analytical and clinical performance of a new automated immunoassay for PGRN measurement applied on Chorus EVO (DIESSE Diagnostica Senese, Siena, Italy) compared to PGRN Mediagnost. Methods: Residual K2EDTA plasma samples from patients suffering from different neurodegenerative disorders have been used for progranulin measurement. Five plasma pools at different concentrations have been adopted to evaluate the analytical performance of the new method. Statistical analysis was performed using MedCalc program. Results: A total of 126 patients have been recruited. For 61 of them, genetic screening for GRN or other mutations has been carried out. The within-series imprecision (CV%) of the automated method ranged from 3.8% to 10.8% and the between-run CV% from 5.6% to 10.7%. Good agreement and correlation between the two methods were observed. ROC curves have been performed to compare genetic testing (GRN mutation carriers) and progranulin results: genetic testing vs. PGRN Mediagnost, AUC of 0.817 (cut-off: ≤17.6 pg/L, sensitivity 66.7%, specificity 92.5%); genetic testing vs. PGRN Chorus EVO, AUC of 0.985 (cut-off: ≤19.6 pg/L, sensitivity 100%, specificity 95.4%). Conclusions: The reported results demonstrate satisfactory analytical and clinical performance of the new automated method, which is suitable for the adoption in clinical practice.