NPM1 Methodology:  
RNA is extracted using the Maxwell SimplyRNA blood kit (Promega). cDNA is synthesised by reverse transcription using the SuperScript IV VILO cDNA synthesis kit (ThermoFisher). Real-time PCR is performed to quantify mutant NPM1 transcripts according to Gorello et al [Leukemia 2006 20: 1103] and Ivey et al [N Engl J Med 2016 374: 422] and ABL1 transcripts according to Gabert et al [Leukemia 2003 17: 2318]. This assay carries a limit of detection 10 copies mutant NPM1 per 100 000 copies ABL1 (0.01%) when 2 microgram of RNA is utilised. 

MRD high is defined as greater than 1000 copies mutant NPM1 transcripts per 100 000 copies ABL1 (bone marrow) or greater than 200 copies mutant NPM1 transcripts per 100 000 copies ABL1 (peripheral blood). MRD low is defined as the presence of mutant NPM1 transcripts at less than 1000 copies per 100 000 copies ABL1 (bone marrow) or less than 200 copies per 100 000 copies ABL1 (peripheral blood). MRD negative is defined as the absence of detectable mutant NPM1 transcripts (Dillon et.al [Blood 2020 135: 680]). Assay sensitivity is calculated according to Schuurhuis et al [Blood 2018 131:1275].