Collecting DNA Evidence at Property Crimes
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Blood and Body Fluid Collection

Home > 3. Evidence Collection > Blood and Body Fluid Collection

The most common methods used to collect blood and body fluid evidence include the following:

  • Cuttings. Remove a section of the item containing the stain using a sterile or clean cutting device.
Cutting carpet containing stain

Image courtesy of Kansas Bureau of Investigation

Removing a section of carpet containing a stain using a sterile cutting device

  • Wet absorption. A sterile swab, gauze pad or threads slightly moistened with distilled water. Concentrate the stain in a localized portion of the swab or pad. When a swab is used, the stain should be concentrated on the tip. The collection medium is pressed or rubbed into the stain and allowed to air-dry. Some laboratories recommend following the first moistened swabbing with a second dry swabbing to ensure thorough sample collection. Both swabs are retained and submitted for analysis.
  • Scraping method. The sample is scraped with a clean razor blade or scalpel, into a clean piece of paper that can be folded and packaged in a paper envelope. This is a method to be used in a controlled environment (i.e., no wind or traffic) and where the scrapings will not contaminate other evidence.



Click here to open and save a double-sided printable version of bindle paper. (PDF)

Video Camera

Click here for a video demonstration of scraping dried blood into bindle paper.

  • Tape-Lifting method. An optional method for collecting dried blood stains on a nonabsorbent surface is using fingerprint tape. The fingerprint-lifting tape may be placed over the stain and lifted off. The stain is transferred to the adhesive side of the tape, which may then be secured on a clear piece of acetate for submission to the laboratory. Note: When using this method, the collector must ensure the fingerprint tape is not contaminated with other biological materials.

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