An Evaluation of Tetramethylbenzidine as a Presumptive Test for Blood

In forensic use, a presumptive test indicating the possible presence of blood is an invaluable tool. This type of test has particular value in screening out samples that are definitely not blood and do not require further testing. Used in this manner, a test should be sensitive to some component of blood which remains even after the blood has dried, aged, or become diluted. This ideal test should also be specific. No such ideal specific test actually exists; however, the tests that are currently used have been characterized, and remedies for nonspecific reactions have been devised [1]. Since a presumptive test is used for screening, it should be simple to use and provide rapid results. Any test should be safe for the examiner applying it.