DNA SAMPLE PROCESSING continued
Figure 1 – Expert system software. Color-coded flagging alerts the analyst to any profiles that failed analysis parameter(s). In this example, the flag- ging includes red in the file name list for each profile that fired analysis rule(s), a red marker label above the electropherogram indicating this positive control is missing allele 9, and quality flags in the report table at right. Linked navigation displays the selected region in the electrophero- gram and report table, making analysis review more efficient and allow- ing analysts to focus on the samples that require evaluation.
Figure 3 – An analyst examines evidence for biological fluid using UV light technology.
Sample quality An important consideration when selecting a DNA sample management solution is sample quality. Samples must be barcoded to ensure proper identification. Most LIMS software programs require laboratories to bar- code reagents, track instrument maintenance and utilize set protocols. “You can’t use expired reagents, and you can’t use an instrument that hasn’t been calibrated,” Hoey offered. “All of these aspects portend good quality.”
One of the slowest parts of the DNA sample management process is reviewing the casework. Each DNA case must undergo a technical and administrative review. An electronic solution can dramatically reduce the review time by allowing analysts to focus on interpretations and conclu- sions rather than clerical review.
Figures 2 and 3 show analysts examining evidence at the Kansas City, Missouri, Police Department Crime Laboratory.
Conclusion DNA sample processing is a high priority in forensics laboratories because
Figure 2 – An examiner studies a shirt for the presence of body fluids.
Sample removal While laboratory equipment automation and electronic sample manage- ment are becoming the foundation for increased efficiency, they do not provide faster DNA processing. “One of the most important aspects is to look at [the] process and determine if non-value-added steps [can be taken out] and what this will do to [the] process, and then begin the cus- tomization from there,” said Missouri DNA technical leader Hoey, whose laboratory uses STACS-CW software. The software was customized for the laboratory to allow samples to be removed at certain points in the sampling process to avoid pushing them all the way through. (Note: the original version of the software necessitated that the sample be pushed through the DNA process regardless of whether it would work or not. With the customized software, the sample could be stopped, that is, the sample with no DNA could be removed and replaced with another sample.)
cases are very often time-sensitive and results can greatly impact law enforcement and the solving of cases. While sample processing cannot be hurried, it can be expedited using good management processes and automation. The software used for this purpose must be modifiable for a laboratory’s validated procedures, protocols and workflows. Scientists and analysts need the ability to track samples all the way through the sampling process, and move data into different workflows or back it up and reprocess it if need be. It is essential to know exactly where a sample is in the process so that errors can be addressed, and to ensure the sample can be appropriately prioritized.
An electronic DNA sample processing solution that is able to grow with the laboratory will undoubtedly help to reduce DNA sample backlogs and increase quality.
Dr. Joanie Brocato, Ph.D., is DNA manager at the Louisiana State Police Crime Laboratory (LSPCL), 376 E. Airport Dr., Baton Rouge, La. 70806, U.S.A.; tel.: 225- 925-6216; e-mail:
joanie.brocato@
la.gov;
www.lsp.org
AMERICAN LABORATORY • 32 • AUGUST 2015
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