title: Impact of Storage Time on Hepatitis B Virus DNA Stability in Clinical Specimens Determined by Quantitative Real-time PCR.
abstract: BACKGROUND
  Detecting blood levels of hepatitis B virus (HBV) DNA must be accurate and credible. Shipment and storage conditions of clinical samples affect the quality of nucleic acids and can interfere with HBV DNA analysis. The aim of our study was to compare HBV DNA stability in plasma specimens at 4 degrees C for different storage periods.
  
  
  METHODS
  Blood samples from 30 hepatitis B surface antigen (HBsAg) positive patients were collected in tubes containing EDTA-K2. Each sample was divided into eight aliquots, one of which was measured immediately for the initial viral load. The remaining aliquots were then stored at 4 degrees C and assessed after 1, 2, 3, 7, 14, 21, and 30 days of storage. Quantification of HBV DNA was performed by real-time polymerase chain reaction (RT-PCR), and the difference in HBV DNA concentrations between two different time points was analysed with a paired-samples t-test.
  
  
  RESULTS
  HBV DNA was measured in a range of 2.00 - 8.00 IU/mL, with low within-run and between-run coefficients of variation (< 10%). Storing plasma for one month at 4 degrees C revealed no significant decrease in HBV DNA level (p = 0.231), and no trend was evident to indicate continued reduction over a 3-week storage period.
  
  
  CONCLUSIONS
  Based on the results of this study, storing plasma for up to one month at 4 degrees C does not affect the stability of HBV DNA, regardless of the initial viral load.
authors.forename: Xiaolian
authors.initials: X
authors.lastname: Zhang
authors.forename: Dongmei
authors.initials: D
authors.lastname: Yang
authors.forename: Yu
authors.initials: Y
authors.lastname: Lu
authors.forename: Xianjun
authors.initials: X
authors.lastname: Lao
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
authors.forename: Shan
authors.initials: S
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001793:Blood Preservation; D004279:DNA, Viral / Q000097:blood* / Q000737:chemistry; D005260:Female; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013997:Time Factors
chemical_list: D004279:DNA, Viral