AutoMate Express™ DNA Extraction System FAQs
Q: What is the AutoMate Express™ System?
A: The AutoMate Express™ System is a 13 prep, cartridge based, bench-top DNA Extraction system developed specifically for extraction of forensic samples using the PrepFiler™ chemistry.
Q: Is the AutoMate Express™ Forensic DNA Extraction System completely automated?
A: The AutoMate Express™ Instrument completely automates the DNA isolation step of DNA purification (binding, washing and elution). Lysis is carried out offline.
Q: Are there any improvements to the offline lysis step for the AutoMate Express™ System?
A: Both the PrepFiler Express™ and the PrepFiler Express BTA™ Forensic DNA Extraction Kits contain the new PrepFiler LySep™ Column. This is an innovative column that eliminates the liquid transfer and substrate removal steps in the lysis protocol by combining lysis and separation into a single column. This significantly reduces the amount of hands on time and helps to reduce the chance of contamination and sample transposition events.
Q: Does the AutoMate Express™ have barcoding capability?
A: Yes. Each AutoMate Express™ System comes with its own barcode reader. The barcode reader can connect to any computer via USB and can be used with the AutoMate Express™ Barcoding Utility, an Excel based template that tracks run, sample, and reagent information. This barcode utility and user guide can be downloaded from www.appliedbiosystems.com/automateexpress
Q: What features are included with the AutoMate Express™ Barcode Utility?
A: The AutoMate Express™ Barcode Utility will track and scan kit and part number as well as the expiration date of the PrepFiler Express™ or PrepFiler Express BTA™ kits. In addition, run information such as AutoMate Express™ serial number, run start and end, and several others can be manually entered and recorded in the utility. Sample and Elution Tube barcodes as well as AutoMate Express™ lane position can also be scanned and checked to ensure proper placement and setup of samples in the AutoMate Express™ Instrument. Finally, a report is generated with all scanned and entered information for inclusion in a case report as well as an HID EVOlution compatible export for qPCR and/or STR setup.
Q: What are some key things to remember when comparing different extraction methods?
A: There are several variables that can drastically affect the outcome of an evaluation of DNA extraction methods. Some important ones to keep in mind are:
- STR profiles are as important or more important when comparing extraction method performance. Superior yield is not as meaningful if you can not get an informative profile. The number 1 goal of forensic DNA analysis is to obtain the most information (i.e., full profile) from evidentiary samples.
- Initial comparisons should be performed on a standard sample type. A single draw of blood from a single donor is preferred. Saliva or buccal swabs can be highly variable and are not ideal for comparisons. The method of preparation of the sample should also be consistent for comparison samples, e.g. dilution method, substrate used and its size, and method of application of the body fluid to the substrate.
- You must test enough replicates to identify potential outliers in the data set. This will provide a sense of overall performance given the variable nature of the process and sample types.
- Low level samples (e.g. < 0.1ng/ul) are not ideal for comparison as stochastic effects can impact PCR based quantitation results and potentially STR results from replicate to replicate. These may be interesting samples to evaluate to get a sense of a system’s performance but are not ideal for comparing methods head to head. Evaluation should be performed with caution and with an appreciation for the stochastic variability.
For more in-depth information, please see the article "Guidelines and Considerations for Evaluating or Validating Extraction Chemistry" in the July 2010 edition of Forensic News.