Physicians will use a combination of blood, urine and bone tests in order to diagnose and monitor someone with MM. Some tests, such as serum protein electrophoresis (SPEP)
and immunofixation (IFE)
are based on the detection of the M-protein in a patient’s serum.
Both SPEP and IFE are non-invasive, inexpensive and widely available blood tests for the routine detection and quantification of M-protein. However, their low sensitivity does not make them appropriate for MRD monitoring.
To measure MRD, highly sensitive tests, such as next generation flow cytometry (NGF) and next generation sequencing (NGS), are used to estimate the myeloma tumor burden by detecting any cancer cells from a standard sample of 1,000,000 cells (106 cells) taken from the bone marrow. However, these methods require painful bone marrow aspirations and occasionally result in false negative readings as a result of sampling bias due to the patchy nature of MM in the bone marrow.
Newly developed mass spectrometry-based blood tests, such as EasyM™, are able to combine the best advantages of the above mentioned approaches by being able to provide a simple non-invasive blood-based test that is as sensitive as bone marrow-based assays in order to reliably monitor MRD throughout treatment.