SPIDIA-DNA: an External Quality Assessment for the pre-analytical phase of blood samples used for DNA-based analyses.

BACKGROUND: The EC-funded project SPIDIA is aimed to develop evidence-based quality guidelines for the pre-analytical phase of blood samples used for DNA molecular testing. To this purpose, a survey and a pan-European External Quality Assessment (EQA) were implemented. METHODS: SPIDIA facility sent to all the participants the same blood sample to be processed without time or temperature limitation. DNA quality parameters performed at SPIDIA facility included: UV spectrophotometric analysis of DNA purity and yield, PCR interferences study by Kineret software and DNA integrity analysis by pulsed field gel electrophoresis. RESULTS: 197 applications have been collected from 30 European countries. A high variability of DNA fragmentation was observed whereas purity, yield and PCR interferences had a narrow distribution within laboratories. A significant difference between the RNase P single copy gene quantity obtained in the DNA samples extracted with the precipitation-based method respect to those obtained with beads and column-based methods was observed. CONCLUSIONS: The results of this study will be the basis for implementing a second pan-European EQA and the results of both EQAs will be pooled and will provide the basis for the implementation of evidence-based guidelines for the pre-analytical phase of DNA analysis of blood samples