Table 1.

Revised International Staging System (R-ISS) stages according to Palumbo et al. [63].

I	Serum β2 microglobulin < 3.5 mg/L
	Serum albumin ≥ 3.5 g/dL
	Normal serum lactate dehydrogenase
	No high-risk cytogenetics *
II	Not meeting criteria for Stages I or III
III	Serum β2 microglobulin > 5.5 mg/L and at least one of the following:
	-Elevated serum lactate dehydrogenase
	-High-risk cytogenetics *

* High risk defined as: presence of del(17p) and/or translocation t(4;14) and/or translocation t(14;16) according to fluorescent in-situ hybridization (FISH) studies.