title: Proficiency testing protocol.
authors.affiliation: Clinical Laboratory Medicine, Douglaston, NY, USA. jaob@consultant.com
authors.forename: Judith A
authors.initials: JA
authors.lastname: O'Brien
mesh_terms: D002624:Chemistry, Clinical; D019411:Clinical Laboratory Techniques; D003625:Data Collection; D007753:Laboratories / Q000592:standards*; D015397:Program Evaluation / Q000379:methods*; D011786:Quality Control