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Levitas, Inc. (www.levitasbio.com) is developing an instrument, reagents, consumables, and a processing protocol that has the potential to significantly reduce the complexity and difficulty of differential extraction (DE) as presently employed at forensic laboratories while enhancing reproducibility and sensitivity. To optimize the utility of the instrument, perfect the protocol and obtain required verification for crime lab use, researchers from Levitas, Inc. are soliciting comments from crime lab scientists and other specialists in forensic DNA identification. The Survey below lists key concerns regarding DE that we welcome your views on. The Survey responses will be analyzed in a Summary Report which will be publicly available on our website.   No individual respondent identifying information will be disclosed in any compilation or analysis of the results.


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* 1. How many sexual assault samples/swabs does your lab process per year (please count only samples subject to differential extraction)?

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* 2. Is your lab using “conventional” differential extraction to separate sperm from epithelial (or other) cells?

Conventional differential extraction is defined as: lysing the epithelial cells, pelleting of sperm cells by centrifugation, collecting the supernatant, isolating soluble DNA from the epithelial cells, and finally sperm cell digestion in preparation for DNA extraction and typing.

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* 3. If your lab uses methods in addition to, or modifications of, conventional differential extraction to separate sperm from epithelial cells, please specify those additional methods (check all that apply):

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* 4. Are any “new” (e.g., under study, not yet validated, experimental) cell separation technologies being used in your lab to separate spermatozoa from epithelial cells?

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* 5. Is any automated equipment used in your differential extraction (or other cell separation) process? If so, what equipment?  (check all that apply)

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* 6. Is any automated processing of differential extraction in consideration for future use in your laboratory?

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* 7. If you presently employ automation, what process steps is it used for? (Check all that apply)

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* 8. How many samples are typically run as a “batch” for DE?

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* 9. Assuming 90% purity, what is the minimum quantity of male DNA that must issue from differential extraction such that CODIS-qualified DNA typing can occur?

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* 10. Assuming 150pg of male DNA is obtained, what is the minimum purity of male DNA that must issue from differential extraction such that CODIS-qualified DNA typing can occur?

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* 11. Is imaging (visualization) and/or cell counting for sperm and/or epithelial cells a requirement in your current workflow?

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* 12. If imaging (visualization) and/or cell counting was incorporated into the separation protocol, how likely would you be to utilize such imaging?

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* 13. What percent of a SAK swab and elute is reserved for differential extraction and downstream analysis?

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* 14. What is the typical buffer volume used to elute from a SAK swab (before spin)?

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* 15. Considering current DE methods, please rank the following concerns from 1-5, where 1 represents the greatest need for improvement:

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* 16. What additional cell mixtures is your lab interested in separating to obtain CODIS-qualified DNA typing?  (check all that apply)

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* 17. Please indicate your preference

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* 18. Thank you for your participation. Please look for the published results at the website of Levitas, Inc. If you are interested in further discussing the technical/scientific issues raised in this Survey, please feel free to leave an e-mail or phone number and a researcher from Levitas, Inc. will follow-up with you.

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