NCJ Number
218232
Journal
Forensic Science Communications Volume: 1 Issue: 2 Dated: July 1999 Pages: 1-15
Date Published
July 1999
Length
15 pages
Annotation
This study analyzed the dependability typically attributed to presumptive tests for bloodstains and extended the study to other reagents used in presumptive tests.
Abstract
This study questions the dependability usually attributed to presumptive tests. It was found that throughout the process a stain that was clearly a bloodstain gave a negative result. This result is a false negative. Results of the study found that a reduction compound (ascorbic acid) added to the blood sample might give rise to a false-negative result for the test. This occurred regardless of the type of sample used (liquid, stain, or print), although different degrees of sensitivity were observed. Preliminary steps in a bloodstain investigation should provide precise and reliable results. There are several steps normally taken in a stain investigation. However, final steps can be eliminated when the chemical tests are performed and a negative result is obtained. It would then be concluded that it is not bloodstain or that only an imperceptible amount of blood is present. This study sought to demonstrate that reduction substances contaminating a bloodstain might prevent a positive test result from being observed. References, tables and figures