However, as opposed to what we observed for total cfDNA, the comparison between ctDNA and parameters related to MM tumor mass revealed a significant correlation, particularly for b2-microglobulin (r = 0.48, p value ≤0.001), albumin (r = −0.23, p value = 0.006) and total BM plasma cells (r = 0.32, p value ≤0.001). Here, ALB is linked to neoplasm.