title: Results of a proposed breath alcohol proficiency test program.
abstract: Although proficiency test programs have long been used in both clinical and forensic laboratories, they have not found uniform application in forensic breath alcohol programs. An initial effort to develop a proficiency test program appropriate to forensic breath alcohol analysis is described herein. A total of 11 jurisdictions participated in which 27 modern instruments were evaluated. Five wet bath simulator solutions with ethanol vapor concentrations ranging from 0.0254 to 0.2659 g/210 L were sent to participating programs, instructing them to perform n = 10 measurements on each solution using the same instrument. Four of the solutions contained ethanol only and one contained ethanol mixed with acetone. The systematic errors for all instruments ranged from -11.3% to +11.4% while the coefficient of variations ranged from zero to 6.1%. A components-of-variance analysis revealed at least 79% of the total variance as being due to the between-instrument component for all concentrations. Improving proficiency test program development should consider: (1) clear protocol instructions, (2) frequency of proficiency testing, (3) use lower concentrations for determining limits-of-detection and -quantitation, etc. Despite the lack of a biological component, proficiency test participation should enhance the credibility of forensic breath test programs.
authors.affiliation: Washington State Patrol, Seattle, WA 98102, USA. Rod.Gullberg@wsp.wa.gov
authors.forename: Rod G
authors.initials: RG
authors.lastname: Gullberg
authors.forename: Barry K
authors.initials: BK
authors.lastname: Logan
mesh_terms: D000096:Acetone / Q000032:analysis; D001944:Breath Tests / Q000295:instrumentation*; D002492:Central Nervous System Depressants / Q000032:analysis*; D019411:Clinical Laboratory Techniques / Q000592:standards*; D000431:Ethanol / Q000032:analysis*; D005554:Forensic Medicine / Q000592:standards*; D006801:Humans; D011786:Quality Control; D012997:Solvents / Q000032:analysis; D014481:United States
chemical_list: D002492:Central Nervous System Depressants; D012997:Solvents; D000096:Acetone; D000431:Ethanol