Quality systems for unit-use testing devices.

Abstract

Unit-use testing or single-test-system analysis has existed for many years. Quality-control and quality-assurance procedures have generally used conventional methods and lyophilized or aqueous control materials. Because these materials were readily available and generally accepted, they became part of the quality-assurance program for many early unit-use test systems such as the DuPont aca. Over the years, these control products became standard and are now required as part of good laboratory practice. Technically speaking, however, conventional quality-control methods and materials cannot completely control the test system when used in a unit-use or single-test-system device. When conventional control material is run on a unit-use single-test system, only that testing unit is checked. One cannot test every unit with control material because by definition these are single-test systems: Once the control has been run, the patient's sample cannot be run. Conventional quality-assurance and quality-control methods do not, of themselves, assure quality. A one-size-fits-all, or "two levels per day of use" as outlined in the CLIA '88 regulations, is not appropriate. The divergence between HCFA-approved practices and those of the deemed agencies, coupled with the financial aspects of this quality-control method, led to the formation of the Subcommittee on Unit Use Testing of the National Committee on Clinical Laboratory Standards to develop guidelines for manufacturers, users, and regulators to use in developing new quality systems.