title: Pre-analytical factors that influence the interpretation of prothrombin time in the clinical laboratory: one year experience in a super speciality hospital in India.
abstract: BACKGROUND
  Accuracy and precision of Laboratory results is a top most priority in a clinical laboratory. Errors in Laboratory results could be due to pre-analytical, analytical and postanalytical variables. Here, we have discussed about pre-analytical variables during estimation of prothrombin time.
  
  
  METHODS
  15,335 PT (prothrombin time) samples received in the department of clinical biochemistry from June 2008 to May 2009 were evaluated for the prevalence of pre-analytical errors. The prothrombin time (PT) was analyzed on automated coagulometer-ACL 7000 with thromboplastin reagent supplied by Trinity Biotech, Ireland.
  
  
  RESULTS
  Out of the 15,335 samples received in one year for analysis by the department, 464 samples showed the presence of pre-analytical variables and therefore, could not be assayed. Among the pre-analytical variables, inappropriate proportion between blood and anticoagulant was the most common error with a frequency of approximately 60%. Clotted samples and illegible handwriting accounted for another 15% each of the rejections respectively. Around 6% of the samples were hemolysed and another 2% were rejected due to lipemia.
  
  
  CONCLUSIONS
  Appropriate knowledge of blood sample collection is a need of an hour to have accuracy in Laboratory results.
authors.forename: Binita
authors.initials: B
authors.lastname: Goswami
authors.forename: Devika
authors.initials: D
authors.lastname: Tayal
authors.forename: Ranjna
authors.initials: R
authors.lastname: Chawla
authors.forename: V
authors.initials: V
authors.lastname: Mallika
mesh_terms: D001800:Blood Specimen Collection; D006801:Humans; D007194:India; D007755:Laboratories, Hospital / Q000592:standards; D011517:Prothrombin Time / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity