title: Prothrombin time, activated partial thromboplastin time and dilute Russell's Viper Venom times are not shorter in patients with the prothrombin G20210A mutation, and dilute Russell's Viper Venom time may be longer.
abstract: BACKGROUND
  Prothrombin G20210A (PT20210) carriers have increased prothrombin levels and increased risk for venous thrombosis. We hypothesized PT20210 carriers would have decreased PT, aPTT, and dRVVT clotting times.
  
  
  METHODS
  We reviewed 1186 thrombotic risk panels that included PT, aPTT, dRVVT, and PT20210 genotype with potential confounding variables, excluding samples consistent with anticoagulant therapy or lupus anticoagulant presence. We examined relationships of PT20210 with PT, aPTT, and dRVVT correcting for covariates using multivariate regression. We confirmed associations in 1876 separate panel results and a group of homozygotes for PT20210 and used general linear models to determine if associated tests predict PT20210 status.
  
  
  RESULTS
  Neither PT, aPTT, nor dRVVT was shorter in PT20210 carriers. Contrary to our hypothesis, PT20210 was significantly associated with higher dRVVT (p=0.001), but not PT or aPTT. dRVVT differences were significant in a replicate sample p=0.035 and an additional sample of PT20210 homozygotes (p=0.02). Of all variables available, only dRVVT predicted PT20210 carrier status (p=0.0008, AUC=0.64).
  
  
  CONCLUSIONS
  We observed an association between longer dRVVT and the prothrombin G20210A mutation in a retrospective observational study. These findings merit further study in large well-characterized clinical cohorts and laboratory research experiments.
authors.affiliation: Department of Pathology, University of Utah Medical Center, Salt Lake City, UT 84124, USA
authors.forename: Brian H
authors.initials: BH
authors.lastname: Shirts
authors.forename: George M
authors.initials: GM
authors.lastname: Rodgers
authors.forename: Kristi J
authors.initials: KJ
authors.lastname: Smock
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010314:Partial Thromboplastin Time; D011516:Prothrombin / Q000235:genetics*; D011517:Prothrombin Time; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D011516:Prothrombin