Abnormal plasma cell infiltration in the bone marrow can be patchy, and if the sample obtained is not representative of the true marrow picture, or has a low proportion of clonal plasma cells, the detection of plasma cells can be missed. Unfortunately, this degree of an increase in the involved free light chain with resultant abnormal K/L ratio is typically suggestive of progressive disease. It may just be early biochemical progression, but organ function would have to be assessed as well to find out if the increase in the free light chain has led to organ damage. Please discuss carefully with your physician about the various options that are available.