Evaluation of prognostic factors and risk stratification in newly-diagnosed patients is important to define treatment strategies, compare outcome of therapeutic trials and predict survival from diagnosis. The 2011 IMWG guidelines for risk stratification  state that the International Staging System (ISS) , incorporating serum albumin and β2-microglobulin (β2M), is applicable as a prognostic system in the majority of settings (Section 20.1).
The guidelines state that other factors may play significant roles in risk stratification, including extramedullary or plasmablastic disease, plasma cell leukaemia, renal failure, lactate dehydrogenase (LDH), IgA, high sFLCs and an abnormal κ/λ sFLC ratio.
Earlier staging systems included concentrations of monoclonal immunoglobulins. It has now been realised that these have little relevance to MM outcome. For IgG MM this may be due to variable recycling by FcRn receptors (Chapter 3). By contrast, elevated sFLC concentrations and abnormal κ/λ sFLC ratios do relate to disease stage and outcome (Chapter 20). This may be due to their more consistant clearance, capacity to cause renal damage (Chapter 26), and their association with IgH translocations .