ISSN: 0022-1198
CODEN: JFSCA
Page Count: 3

The Presumptive Reagent Fluorescein for Detection of Dilute Bloodstains and Subsequent STR Typing of Recovered DNA
Budowle, B
Scientific Analysis Section, FBI Academy, VA

Defenbaugh, DA
Scientific Analysis Section, FBI Academy, VA

Leggitt, JL
Evidence Response Team Unit, FBI Academy, VA

Keys, KM
Scientific Analysis Section, FBI Academy, VA

Malkiewicz, SF
Evidence Response Team Unit, FBI Academy, VA

(Received 3 September 1999; accepted 22 November 1999)

Abstract

A presumptive reagent for dilute blood detection other than luminol is fluorescein. The sensitivity of fluorescein approaches the sensitivity of detection levels of luminol. The fluorescein detection method offers the advantages of working in a lighted environment, and the reaction persists longer than luminol. A series of diluted bloodstains, ranging from neat to 1:1,000,000, was placed on a variety of substrates. Three sets were made per substrate. One set was exposed to fluorescin, one set was exposed to luminol, and one set served as an uncontaminated control. The fluorescein signal persisted longer than luminol. However, background staining for fluorescein was observed on some substrates within 30 s to 1 min, and no background staining was observed for luminol. Stains on non-absorbent surfaces were detectable at 1:100,000 dilutions, and stains on absorbent surfaces were detectable usually at no more than 1:100. The sensitivity of detection of fluorescein was comparable to that of luminol in this study. In all cases, where sufficient DNA was recovered, typeable results at all 13 core CODIS STR loci were obtained from treated bloodstains and controls. The results from STR typing indicate that there was no evidence of DNA degradation.

Keywords:
forensic science, fluorescin, fluorescein, luminol, blood identification, DNA typing, short tandem repeats

Paper ID: JFS14835J
DOI: 10.1520/JFS14835J
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