Table 1.

Criteria of RISS, DSS, and DS Plus staging systems.

	RISS [6]	DSS [4]	DS Plus [8]
Stage I	ISS stage I (serum albumin ≥3.5 and serum β2-microglobulin <3.5), normal LDH levels, and no high-risk cytogenetic abnormalities	All of the following: hemoglobin value >10 g/dL; serum calcium value normal or ≤10.5 mg/dL; bone X-ray shows normal bone structure or solitary bone plasmacytoma only; and low M-component production rates (IgG < 5 g/dL, IgA < 3 g/dL, and Bence Jones protein < 4 g/24 h)	Stage IA, smoldering or indolent: single plasmacytoma and/or limited disease at imaging Stage IB: 0–4 focal lesions or mild diffuse disease
Stage II	Neither stage I nor stage III	Neither stage I nor stage III	5–20 focal lesions or moderate diffuse disease
Stage III	ISS stage III (serum β2-microglobulin >5.5 mg/L) and either elevated LDH levels or high-risk cytogenetic abnormalities	One or more of the following: hemoglobin value <8.5 g/dL; serum calcium value <12 mg/dL; advanced lytic bone lesions; and high M-component production rates (IgG > 7 g/dL, IgA > 5 g/dL, or Bence Jones protein >12 g/24 h)	>20 focal lesions or severe diffuse disease
Subgroup A	—	Relatively normal renal function: serum creatinine value <2.0 mg/dL	Serum creatinine level <2.0 mg/dL and no EMD
Subgroup B	—	Abnormal renal function: serum creatinine value ≥2.0 mg/dL	Serum creatinine level >2.0 mg/dL and/or the presence of EMD