ABSTRACT
Several simple and rapid presumptive tests for the detection of urine are available. In 1886, Jaffe, a German biochemist, developed a presumptive test for the detection of creatinine (a waste product) that is secreted in urine (Jaffe, 1886; Gaensslen, 1983). The test is based on the reaction of picric acid with creatinine and a weak base to form a deep orange-red color. In 1948, Cook developed a test for urine that detects urea using an enzyme called urease. In the presence of urease, urea is cleaved to form ammonia, which is detected using bromothymol blue, an acid-base indicator. The test is conducted using litmus paper, and if a positive reaction occurs, the paper will turn from red to a bright blue color. Most forensic laboratories use either the Jaffe color test for creatinine or the urease test for urea as a presumptive screen. To confirm the presence of urine, which will consume an additional sample, a test kit (BFID-Urine) is commercially available through Independent Forensics, Hillside, Illinois.
