The Revised International Staging System (R-ISS) includes variables from the original ISS (serum β2-microglobulin and serum albumin), as well as high-risk chromosomal abnormalities detected by CD138 magnetic bead sorting combined with interphase fluorescence in situ hybridization (iFISH) and serum LDH as prognostic indicators. The revised international staging system criteria are as follows: Stage I: Meets ISS stage I criteria, iFISH test shows non-cytogenetic high-risk patients, and LDH is normal. Stage II: Between R-ISS stages I and III. Stage III: Meets ISS stage III criteria, iFISH test shows high-risk chromosomal abnormalities or elevated LDH.