Progastrin-Releasing Peptide Is a Candidate Marker for Quality Control in Clinical Sample Processing and Storage

For clinical epidemiologic and proteomic studies, the control of preanalytic variation, including sample processing and storage, is important. We evaluated the stability of progastrin-releasing peptide (ProGRP) as a marker for the quality control of stored serum and plasma samples. The ProGRP from 23 healthy volunteers was measured serially for 8 hours at room temperature, and the results were validated with clinical samples from the biobank. A significant difference in ΔProGRP was also noted between good-quality (time delay <4 hours before storage) and poor-quality (time delay ≥4 hours before storage) specimens (mean ± SD, 0.17 ± 0.08 vs 0.36 ± 0.14; P < .001; Wilcoxon signed-rank test). With a ΔProGRP cutoff of 0.22, the sensitivity and specificity of detection of the poor-quality samples were 85.7% and 75.0%, respectively, in clinical validations. We demonstrated that ΔProGRP could be used as a marker for quality control in sample processing and storage in biobanks.