We describe the origins, purposes, and findings of a national study to determine whether a large-scale program of blind proficiency testing in U.S. DNA laboratories is feasible and/or practical. Proficiency testing in clinical laboratories is reviewed, particularly as mandated by the Clinical Laboratory Improvement Acts and its role in the regulation of those laboratories. Proficiency testing in forensic urine drug testing labs is also briefly reviewed. Studies involving comparisons between open and blind proficiency testing are discussed. The clinical laboratory proficiency testing and regulation landscape provides the background for the DNA Act of 1994, and the congressional mandate to investigate blind proficiency testing in forensic DNA laboratories. Four models of blind proficiency testing are defined and discussed, along with the advantages and disadvantages of each and estimates of the costs of a large-scale program. The purposes of proficiency testing in a quality-assurance context are likewise discussed and related to the models and the arguments generally proffered for and against blind vs. open proficiency testing.

The background and goals of a national study to determine the feasibility of blind proficiency testing in U.S. forensic DNA laboratories are discussed. Part of the project involved designing and executing a series of fifteen blind proficiency tests. Execution included biological specimen donor recruitment and case evidence manufacturing. Simulated cases were submitted to DNA laboratories by law enforcement agencies and in some cases by other forensic-science laboratories. Replicate-manufactured evidence was submitted to reference laboratories to simulate the workings of a larger-scale program. Ten tests were straightforward, and essentially tested analytical ability. Five tests involved selecting on the basis of case facts appropriate bloodstains for typing from a bloodstain pattern. We describe in detail our experience in designing and conducting these blind proficiency test trials, and relate those experiences to the overall issue of blind proficiency testing as a quality-assurance tool in forensic DNA laboratories. In this feasibility test series, one blind test was detected by a laboratory, a second one was shown to the lab by law enforcement, and a third was never completed because of lapses in communication. Turnaround times were relatively fast in the independent/commercial labs and relatively slow in the larger public laboratories. Two cross-state case-to-case CODIS "hits" were "planted" among the first series of ten blind tests. One pair was detected. One member of the second pair went to a lab that was not CODIS-ready.