DNA testing can link an item of evidence to an individual, but it cannot identify the biological fluid from which the genetic material originated. Such basic information, however, is often critical to identifying probative evidence in a criminal investigation. In contrast to the technological advancements in DNA testing, serological identification still relies on classical chemical, enzyme activity, and antibody-based assays. These methods are unable to detect body fluids as vaginal secretions and menstrual blood – both of which are commonly encountered in sexual assault cases. Moreover, for bodily fluids that can be detected, existing technologies yield only a presumptive indication of a target body fluid while often consuming unacceptable quantities of precious evidence.

Fluid1

Researchers at the CFSRE have developed protein mass spectrometry-based techniques for the confirmatory identification of forensically relevant biological fluids. Over the last decade, these improved serological workflows have been developed and validated for forensic applications with the current aims of the CFSRE to increase throughput by automation and a focus on improving sexual assault kit screening.

Benefits

  • Protein mass spectrometry can provide true confirmatory results for six forensically relevant body fluids including peripheral and menstrual blood, vaginal fluid, urine, saliva and seminal fluid.
  • The workflow allows for the simultaneous detection of all six fluids, even in mixed samples.
  • Automation and liquid handling systems have enabled high throughput sample processing.

Applications

Serological research conducted by the CFSRE has provided the forensic community with a novel tool for body fluid identification. In contrast to traditional methods, protein mass spectrometry allows for high throughput confirmatory body fluid identification. Ongoing research at the CFSRE has focused on more streamlined sample preparation workflows and hybrid approaches to forensic body fluid identification. This includes intact protein analysis and protein and peptide immunoaffinity purification prior to mass analysis.

Resources

The CFSRE continues to present this work at national and international conferences as well as in peer-reviewed publications.

Peer reviewed publications

  • Catherine O. Brown, Brianna L. Robbins, Heather E. McKiernan, Phillip B. Danielson, Kevin M. Legg. Direct seminal fluid identification by protease‐free high‐resolution mass spectrometry. J Forensic Sci. 2020 Dec 8. doi: 10.1111/1556-4029.14646
  • Kevin M Legg, Roger Powell, Nichole Reisdorph, Rick Reisdorph, Phillip B Danielson. Verification of protein biomarker specificity for the identification of biological stains by quadrupole time-of-flight mass spectrometry. Electrophoresis. 2017 Mar;38(6):833-845. doi: 10.1002/elps.201600352.