Catherine P Hayward

Publications (2)7.64 Total impact

• Article: Protein C assay performance: an analysis of North American specialized coagulation laboratory association proficiency testing results.

  Jason M Baron, Stephen M Johnson, Marlies R Ledford-Kraemer, Catherine P Hayward, Piet Meijer, Elizabeth M Van Cott
  [show abstract] [hide abstract]
  ABSTRACT: To determine the performance and frequency of protein C reagents currently used by clinical laboratories, we analyzed North American Specialized Coagulation Laboratory Association (NASCOLA) protein C proficiency testing data from 6 surveys conducted in 2009 and 2010 (2009-1 to 2009-3 and 2010-1 to 2010-3). Interlaboratory coefficients of variation (CV) for commonly used reagents on a survey with normal protein C ranged from 8% to 12% for antigenic assays, from 4% to 7% for chromogenic activity assays, and from 7% to 22% for clot-based activity assays. CVs for commonly used reagents on specimens with abnormal protein C ranged from 15% to 24% for antigenic, 4% to 11% for chromogenic, and 10% to 17% for clot-based assays (averaged across 3 surveys). Some reagents were used by relatively few laboratories and therefore additional study may be needed for those reagents. For all commonly used reagents, biases were usually small and often not statistically significant. All assessed reagents were clinically accurate, and were considered acceptable options for a specialized coagulation laboratory.
  American Journal of Clinical Pathology 06/2012; 137(6):909-15. · 2.60 Impact Factor
• Source

  Available from: nascola.org

  Article: Are laboratories following published recommendations for lupus anticoagulant testing? An international evaluation of practices.

  Karen A Moffat, Marlies R Ledford-Kraemer, Elizabeth A Plumhoff, Heather McKay, William L Nichols, Piet Meijer, Catherine P Hayward
  [show abstract] [hide abstract]
  ABSTRACT: Laboratory tests for lupus anticoagulants (LA) are commonly performed to evaluate thrombosis or suspected phospholipid antibody syndromes. To determine current LA testing practices, and if they conform to published recommendations, two questionnaires were distributed to clinical laboratory members of the North American Specialized Coagulation Laboratory Association (NASCOLA) and the ECAT Foundation (ECAT). The first and second questionnaires were completed by 113 and 96 laboratories, respectively. Commonly performed LA tests included the dilute Russell's viper venom time, LA sensitive activated partial thromboplastin time and hexagonal phospholipid test. Although some laboratories did single LA tests if requested, the majority complied with published recommendations: to use platelet poor plasma for LA tests; to use two or more screening tests, representing different assay principles, and one assay having a low phospholipid concentration to exclude LA; to confirm LA phospholipid dependency by the method giving an abnormal LA screen; to document the inhibitor activity on pooled normal plasma; and not to use phospholipid antibodies to confirm LA. A minority (<35%) followed the recommendations to exclude factor deficiencies and factor inhibitors as the cause of an abnormal LA test. After participating, 32% of laboratories had changed practices and 20% indicated that they would be changing practices. While most laboratories generally follow published guidelines for LA testing, few follow recommendations to evaluate for other coagulation abnormalities. Questionnaires may be helpful quality initiatives to improve compliance with laboratory testing guidelines and recommendations.
  Thrombosis and Haemostasis 02/2009; 101(1):178-84. · 5.04 Impact Factor