CFS - Technical Information Sheets - Biology - Blood Information
Technical Information Sheets
Blood Information - PDF, 29 kb (Rescinded Sept. 17, 2012)
Blood is a liquid that circulates through the body, transporting oxygen and nutrients and removing waste products. Blood consists of a liquid called plasma in which blood cells are suspended. Hemoglobin is a component of blood.
Examination for the Presence of Blood
Items are visually examined for any staining that may contain blood. Stains are tested using the Kastle-Meyer test. Stains may also be tested using an ABAcard® to determine whether or not they are of human origin.
Tests for the Presence of Blood
Visual examination: May involve using a stereomicroscope (a magnifying tool) and enhanced light sources.
Kastle-Meyer test (Phenolphthalin test) : A 3-stage chemical test that gives a pink colour reaction in the presence of haemoglobin, a substance specific to blood. This can be performed as a rub or direct test.
ABAcard®, HemaTrace® test: Test used to determine if a bloodstain is of human origin. This test uses commercially prepared reagents that bind specifically to human (higher primate) hemoglobin, allowing for visual detection.
The sensitivity of the Kastle-Meyer testing is such that a positive result may still be obtained in the absence of visible staining.
Although false positive Kastle-Meyer reactions are sometimes obtained with other substances, such as certain fresh plants, as applied at the CFS this test is specific for blood. The Kastle-Meyer test alone does not indicate whether or not the blood is of human origin.
The ABACard® HemaTrace® test is specific to human (higher primate) blood. False negative results are possible when dealing with severely degraded samples. False positive results have been observed with ferret blood.
Direct test - Involves applying the Kastle-Meyer chemicals directly to a sub-sample from the area in question.
Hemoglobin - The component of blood that transports oxygen.
Rub test - Involves rubbing the area in question with paper and applying the chemicals to the paper.