Preanalytical stability of plasma calcitonin gene-related peptide: clinical and research implications.

BACKGROUND: Calcitonin gene-related peptide (CGRP) is a pivotal molecule in migraine pathophysiology and a major target of current therapeutic strategies. Accurate plasma quantification is essential for biomarker research, yet concerns persist regarding its preanalytical stability. OBJECTIVE: To assess the stability of plasma CGRP in relation to clinically relevant delays in sample processing and different centrifugation protocols. METHODS: We conducted an analytical study including 40 healthy participants (22 females, median age 26 years), recruited at the Medical University of Innsbruck, Austria, between January and June 2023. Blood samples were obtained under standardized conditions and processed at predefined intervals (6–180 min), either immediately or following delayed centrifugation. CGRP concentrations were determined by a validated sandwich ELISA. Data analysis included repeated-measures ANOVA with corrections for age and sex, as well as paired t tests. RESULTS: Median plasma CGRP concentrations demonstrated a nonsignificant numerical increase over time, with slightly higher values in women. Repeated-measures ANOVA showed no significant effect of delayed processing on CGRP levels (P = 0.326). The interaction between time and sex was statistically significant (partial η² = 0.069; P = 0.040), but separate analysis for females and males did not yield significant within-subject effects. Immediate versus delayed centrifugation (30 and 60 min) did not significantly influence CGRP concentrations (P = 0.548 and P = 0.305, respectively). CONCLUSION: Plasma CGRP is stable over a range of preanalytical delays and under varying centrifugation conditions. These findings support robust biomarker approaches in clinical and multicenter studies by minimizing concerns about technical variability.