A method for increasing sensitivity for detecting minority mutations in MYD88 uses a locked nucleic acid oligo to block amplification of wild-type DNA in DNA isolated from patient FFPE tissue, bone marrow aspirate or peripheral blood samples during PCR while still allowing sequencing and visualization of the PCR product. Further improvement to the sensitivity may be achieved by using a uracil DNA-glycosylase treatment to remove sequence artifacts commonly found in formalin-fixed, paraffin-embedded tissue.