Interlaboratory variation in heparin monitoring: Lessons from the Quality Management Program of Ontario coagulation surveys

Unfractionated heparin (UFH) monitoring is subject to substantial interlaboratory variation. We analysed results of annual coagulation surveys administered by the Quality Management Program - Laboratory Services (Toronto, ON, Canada) from 2003 to 2007 to evaluate variation in UFH monitoring across Ontario. Participating laboratories performed an activated partial thromboplastin time (APTT) utilising their local methodology on lyophilised human …