The Feasibility of External Blind DNA Proficiency Testing. II. Experience with Actual Blind Tests

Abstract

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.

Particulate capillary precolumns with double-end polymer monolithic frits for on-line peptide trapping and preconcentration

“…Various approaches have been developed to prepare capillary precolumns for nano-flow LC systems, including packed precolumns [9,10], polymer and silica monolithic precolumns [11] and particle-entrapped precolumns by monoliths [5,12]. Although monolithic or particle-entrapped monolithic precolumns are fritless, simplifying the column preparation, such columns suffer from the drawbacks, for example, polymer monolith could not endure high organic solvent, while silica monolith is prone to shrinking and cracking during column drying.…”

Using organizational economics to engage cultural key masters in creating change in forensic science administration to minimize bias and errors

“…Blind proficiency tests have been criticized as being expensive Peterson et al (2003aPeterson et al ( , 2003b. conducted a proof of principle to determine whether blind proficiency tests are feasible.…”

“…(2003a, 2003b) conducted a proof of principle to determine whether blind proficiency tests are feasible. They concluded that for DNA laboratories samples could be manufactured (2003b: 39) and that the expected cost per test would be $2,000 to $3,500 and that economies could be achieved with two tests per laboratory (150 DNA laboratories) (2003a: 40), with a total cost for the two tests per laboratory of $630,000 to $1,035,000 per year. Koppl (2010) states ‘.…”