title: [The external quality measurement: actual problems and future directions].
authors: W Creg
authors: WC
authors: Miller
authors: Graham R D
authors: GR
authors: Jones
authors: Gary L
authors: GL
authors: Horowitz
mesh_terms: D019411:Clinical Laboratory Techniques / Q000379:methods* / Q000592:standards*; D003695:Delivery of Health Care / Q000592:standards* / Q000639:trends; D006801:Humans; D011786:Quality Control