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Impact of storage conditions on genetic analysis or viral load determination in clinical specimens

Abstract Background: Storage and shipment conditions of clinical specimens affect the quality of nucleic acids and may interfere with molecular analysis. The aim of our study was to verify whether blood storage at room temperature affects single nucleotide polymorphisms analysis; moreover, we analysed the consequences of serum storage at +4°C on viral load determination of hepatitis B and C viruses. Methods: For single nucleotide polymorphism screening, genomic DNA was extracted from EDTA whole blood samples stored at room temperature for different times, quantified photometrically, and Factor V Leiden point mutation analysis was performed. For viral load determination, serum samples with medium or low viremias were stored at +4°C for different times and analysed by Cobas AmpliPrep/Cobas TaqMan tests for hepatitis B virus (HBV) DNA or hepatitis C virus (HCV) RNA. Results: While mutation analysis was successfully performed on all samples tested, serum storage at +4°C of HBV- and HCV-infected sera decreased viral load, in particular for low viremias. Conclusions: Storage of blood samples at room temperature up to 1 month does not affect the feasibility of genetic analysis, while serum storage at +4°C affects viral load. Clin Chem Lab Med 2008;46:280–2.