RESUMEN
BACKGROUND: NPM1 plasmid standards are required for absolute quantification of minimal residual disease in acute myeloid leukemia patients. The standards are usually obtained, next to commercially constructed gene fragments, from transgenic bacteria colonies. However, this procedure is laborious and very time consuming. METHODS AND RESULTS: We have developed a PCR method that speeds up, simplifies, and streamlines the process of preparing NPM1 plasmid standards. The method is based on a combination of three primers, two surrounding the usual NPM1 mutation position and one over the mutation site. With this method, we were able to clearly distinguish plasmids with at least 15 different NPM1 mutations from the wild-type NPM1 plasmid. CONCLUSIONS: With the new approach, preparing NPM1 plasmid standards is easier, identifying NPM1-positive colonies is possible in less than a day and moreover, for a lower price than commercially constructed gene fragments.