Reverse transcription real time quantitative PCR (RQPCR) is routinely used to quantify levels of BCR-ABL mRNA transcripts in peripheral blood and bone marrow samples from chronic myeloid leukaemia (CML) patients. The technique can determine accurately the response to treatment and is particularly valuable for patients who have achieved complete chromosomal remission. Despite efforts to establish standardised protocols for BCR-ABL fusion transcript quantitation there is still substantial variation in the way in which RQ-PCR for BCR-ABL is carried out and how results are reported indifferent laboratories worldwide

An international scale (IS) has recently been established recently that is anchored to two key points defined in the IRIS trial: a common baseline (100% BCR-ABLIS) and major molecular response (0.1% BCR-ABLIS). Definition of the IS currently relies on relating results directly or indirectly to the Adelaide international reference laboratory. A more robust definition of the IS requires the development of internationally accredited reference reagents.

NGRL (Wessex) in collaboration with the NIBSC and Asuragen have developed the following prototype reference materials which were field trialled in 2007.

• Freeze dried cell lines

• Armored RNA constructs

Large scale production of the freeze dried cell lines as ‘higher order’ internationally accredited reference materials has been completed and the aRNA constructs will undergo a further round of field trial evaluation.