What are the ISS stage criteria?

Stage I: β2-microglobulin <3.5 mg/L AND albumin ≥3.5 g/dL (median survival 62 months). Stage III: β2-microglobulin ≥5.5 mg/L (median survival 29 months). Stage II: all other combinations.

What is the R-ISS (Revised ISS)?

The R-ISS adds cytogenetics [t(4;14), t(14;16), del(17p)] and LDH to ISS. R-ISS III (ISS III + high-risk cytogenetics or elevated LDH) has the worst prognosis with median OS ~33 months.

How is β2-microglobulin interpreted in myeloma?

β2-microglobulin is both a tumor mass marker and a reflection of renal function. Values must be interpreted alongside creatinine — renal impairment elevates β2M independently of myeloma burden.

ISS International Staging System for Multiple Myeloma

Calculates the International Staging System (ISS) stage for multiple myeloma using serum β2-microglobulin and albumin. Stage I: β2M <3.5 mg/L + albumin ≥3.5 g/dL; Stage III: β2M ≥5.5 mg/L; Stage II: all others.

Use the full interactive calculator below, or

Related Calculators

Durie-Salmon Myeloma Stage

Medical

IPI Lymphoma Score