The amplification refractory mutation system (ARMS) is an amplification strategy in which a polymerase chain reaction (PCR) primer is designed in such a way that it is able to discriminate among templates that differ by a single nucleotide residue (1),2) ARMS has also been termed allele-specific PCR (3) or PCR amplification of specific alleles (PASA) (2). Thus, an ARMS primer can be designed to amplify a specific member of a multi-allelic system while remaining refractory to amplification of another allele that may doffer by as little as a single base from the former. The main advantage of ARMS is that the amplification step and the diagnostic steps are combined, in that the presence of an amplified product indicates the presence of a particular allele and vice versa. For routine diagnosis, this characteristic of ARMS means that It is a very time-efficient method. However, this combination of the amplification and diagnostic steps has resulted in a system that may not be as robust as some of the other methods in which these two important steps are separated, e.g., PCR followed by restriction enzyme analysis.