Extractive versions of the Absorption Elution Test for bloodstain grouping have the advantages of suitability for batch working and the ease of reading the results. The unpopularity of extractive methods, however, can be traced to the difficulty of bloodstain extraction in all but the freshest of stains. It has been shown that dilute ammonia solutions are excellent extractants of denatured bloodstains for ABO grouping. The method should find particular application in warm climates where the heat denaturation of bloodstains is a daily problem for forensic science laboratories. © 1969, Forensic Science Society. All rights reserved.