The HemeSelect TM test was evaluated and compared with the precipitin test for sensitivity and specificity. The test used aged bloodstains (some as old as 18 years), bloodstains (wet and dry) maintained at elevated temperatures, bloodstain extracts serially diluted to 1:100,000, other body fluid stains, animal bloodstains, and casework bloodstains. The HemeSelect TM test is an immunochemical faecal occult blood test distributed by SmithKline Diagnostics. The test is designed to detect the presence of human hemoglobin in stool samples through the use of an anti-human hemoglobin antibody in a reverse passive hemagglutination (RPHA) procedure. It can also be used to determine the species of origin of evidentiary blood or other types of body fluid stains. The primary advantage of this test over the more conventional precipitin test is its superior sensitivity. The HemeSelect TM test was found to be at least two orders of magnitude more sensitive than a precipitin test and would be the test of choice for small or aged stains. 1 figure, 2 tables, and 4 references