Recovery of DNA from SERATEC^Ⓡ immunochromatographic PSA and saliva test strips

Abstract

There is an increased use of immunochromatographic test strips to presumptively identify bodily fluids of forensic interest, such as blood, semen, and saliva.Commonly, forensic samples are of low quantities. In the practice of conserving limited samples, it would be ideal to be able to recover the genetic material deposited on these testing membranes. This research aimed to determine whether DNA could be extracted from semen and saliva test strips, which part of the test strip is best to use, and to assess the quality of the DNA recovered. Semen and saliva samples were deposited on SERATEC ® PSA Semiquant and Amylase Tests and analyzed. The testing membrane was then removed from the cassette and DNA extraction methods (forensicGEM Universal, forensicGEM Sperm, QIAamp ® DNA Mini kit, Monarch ® Nucleic Acid Purification kit, and organic extraction) were performed. Quality was evaluated by qPCR and STR analysis. DNA from semen was best extracted using the Monarch ® Nucleic Acid Purification kit, while saliva was best extracted using the forensicGEM or QIAamp kits. No significant differences were observed between collection of the sample well pad and testing strip, thus use of the entire strip is encouraged. DNA from semen and saliva was quantifiable with a 1:1000 dilution. DNA quality analysis by qPCR showed that there is no difference in the DNA quality following elution from the test strip. However, degradation was noted in saliva samples and some semen samples by STR analysis.Scientists are encouraged to consider processed test strips for DNA profiling to preserve evidence.

Assessment of the efficiency of DNA isolation and profiling applying a temperature‐driven method in human remains

“…The MicroGem protocol was previously assessed for DNA extraction from PSA and saliva immunochromatographic tests, demonstrating better results with saliva with respect to silica-based methodologies [16]. The MicroGem approach has several advantages with respect to the AE extraction and/or silica-based methodologies: It does not require specialized equipment; as it is temperature-driven in a single tube, it reduces the possibility of contamination; previous aforementioned protocols used proteinase K, which requires ionic detergents and the working temperature of which is between 20 and 65 • C; in contrast, ForensicGem enzyme does not require ionic detergents, and its working temperature is 75 • C, which decreases the possibility of introducing inhibitors on the sample.…”

Use of Lateral Flow Assays in Forensics

“…Although the indicative aspect of most LFAs can be seen as a disadvantage (no 'real evidence' can be obtained from indicative LFAs), it may be clear that the initial information that can be gained with these LFAs can help/direct the initial phases of an investigation as well as speed up the (start of the) investigation trajectory. Nevertheless, the use of indicative LFAs implies that confirmation by using conventional methods and techniques is required [63]-for example DNA analysis after the use of LFAs [78]-which seems another aspect that hampers/delays broad use of these LFAs in forensics.…”

Making the Most of Lateral Flow Immunochromatographic Tests: An Efficient Protocol to Recover DNA

“…There have been some attempts to combine these two objectives and be able to identify the body fluid and extract a DNA profile from the sample [ 12 , 13 , 14 , 15 ] and from the LFI test strips [ 16 ], obtaining most of the sample without losing it. Our previous publications also demonstrated successful DNA recovery and profiling from a sample swab [ 17 , 18 ] and LFI test strips [ 19 ].…”