The Bt Cry1Ab/1Ac ELISA is an immunoassay for the qualitative screening detection of Bt Cry1Ab/1Ac protein residues. The Bacillus thuringiensis (Bt) Cry1Ab/1Ac protein is an insecticidal crystalline protein expressed by the Cry1Ab/1Ac gene in certain strains of genetically modified plants. This test is suitable for the qualitative detection of Bt Cry1Ab/1Ac in MON810, Bt11, Bollgard?, Bollgard II?, or WideStrike? corn seed, cottonseed, leaf tissue, sur- face water, and soil samples (please refer to the appropriate sample preparation or extraction). If necessary, positive samples can be confirmed by PCR or other conventional methods.