Resolution of ambiguous low-level positive quantitative polymerase chain reaction results in TEL-AML1 positive ALL using a post-PCR fluorescent oligoligation method

The interpretation of low-level or non-reproducible amplification results in clinical quantitative polymerase chain reaction (Q-PCR) assays can be difficult to definitively resolve. Concerning minimal residual disease detection in leukaemia, indeterminate low-level results might create prognostic or therapeutic dilemmas. We evaluated low-level, ambiguous Q-PCR results in a study of paired diagnostic and end-induction (day 29) TEL-AML1 positive acute lymphoblastic leukaemia samples utilising a novel fluorescent primer ligation detection assay. The data presented here indicate that a significant number of low-level apparent Q-PCR positive results may be spurious or non-specific in nature, requiring additional technical manoeuvres for confirmation of true positive cases.