MutaGEL® Lactase (AS) PCR Assay is an amplification refractionary mutation system (ARMS) containing two sets of primers for both allelspecific sequences within the lactase gene. The sequence specific primers can be used directly for PCR with extracted DNA. The resulting amplification products are subsequently identified with gelelectrophoretic methods. If there is no specific allel-product detectable, the correct PCR procedure is proved by an internal control. The present genotype of unknown samples is interpreted by detection of corresponding DNA-amplificates for wildtype- and mutation-constellation in two separate lanes of the gel (method by Dr. Essrich, Biologisches Labor, Denzlingen).