The Evaluation of Possible False Positives with Detergents when Performing Amylase Serological Testing on Clothing


  • Presented by Ni cole Novroski at the 64th Annual Meeting of the American Academy of Forensic Sciences, February 20-25, 2012, in Atlanta, GA.
  • Funded by the Minnesota Bureau of Criminal Apprehension in Saint Paul, Minnesota.

Additional information and reprint requests:

Andrea Feia, M.A.

Forensic Scientist—Nuclear DNA Lab

MN Bureau of Criminal Apprehension

1430 Maryland Avenue East

St. Paul, MN 55106



For almost 40 years, detergent companies have been adding enzymes such as amylases to their products as an effective method of breaking down tough stains created by polysaccharides and proteins. The possibility that α-amylases present in common household laundry detergents may contribute to the positive detection of α-amylase on evidentiary samples during forensic presumptive screening procedures is a potential problem that has not yet been investigated. To determine whether α-amylase detection is possible following routine laundering, five different fabrics were laundered in a variety of detergents, and presumptive testing using RSID-Saliva and Phadebas® Amylase Test was conducted. Our results demonstrate that clothing laundered in detergents known to contain enzymes does not retain any detectable levels of α-amylase following a typical wash cycle. We also show that, unlike laundered clothing, undiluted detergents do contain detectable levels of α-amylase; however, these findings were only observed using the Phadebas® Amylase Test.