Staging of myeloma

The stage describes how advanced the myeloma may be. The stage of myeloma does not usually affect the treatment that is offered.

What is myeloma staging?

The stage describes how advanced the myeloma is and how effective treatment might be. However, the stage of the myeloma does not usually affect the treatment that is offered. So doctors do not always talk about staging.

We understand that waiting to know the stage of your myeloma can be a worrying time. We're here if you need someone to talk to. You can:

Call the Macmillan Support Line for free on 0808 808 00 00.
Chat to our specialists online.

Types of myeloma

International Staging System (ISS) for myeloma

To find out what stage the myeloma is, doctors use a staging system. The International Staging System (ISS) looks at the results of 2 blood tests:

beta-2 microglobulin (B2M)
albumin level.

If the level of B2M is raised or if the level of albumin is lower than normal, these can be signs that the myeloma is more advanced.

With this staging system, there are 3 stages of myeloma. Stage 1 is the earliest stage and stage 3 is more advanced.

Stage	B2M (measured in mg/L)	Albumin (measured in g/dL)
Stage 1	Normal or near normal (less than 3.5)	Normal (3.5 or more)
Stage 2	Blood test results do not meet stage 1 or 3 criteria
Stage 3	High (5.5 or more)	Any level

Revised International Staging System (R-ISS) for myeloma

Sometimes doctors use an adapted version of the ISS called the Revised International Staging System (R-ISS). This uses:

the results of the blood tests from the ISS
a blood test called lactate dehydrogenase (LDH)
the results of the FISH test, if you had one – this test looks for genetic changes in the myeloma cells.

CRAB criteria for myeloma

The doctors also look at the effect the myeloma is having on the body. They may look at test results using something called the CRAB criteria to assess this. CRAB stands for:

C – calcium levels are raised.
R – renal (kidney) problems.
A – anaemia (low number of red blood cells).
B – bone damage.

The doctors also ask whether you have been having repeated infections or symptoms related to thickening of the blood (hyperviscosity). These may include confusion, headaches or blurred vision.

We have more information about managing myeloma symptoms.

References

Below is a sample of the sources used in our myeloma information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk

Hughes D, Yong K, Ramasamy K, et al. Diagnosis and management of smouldering myeloma: A British Society for Haematology Good Practice Paper. Br J Haematol. 2024;204(4):1193-1206. Available from: www.doi.org/10.1111/bjh.19333

Sive J, Cuthill K, Hunter H, et al. Guidelines on the diagnosis, investigation and initial treatment of myeloma: a British Society for Haematology/UK Myeloma Forum Guideline. Br J Haematol.2021;193(2):245-268. Available from: www.doi.org/10.1111/bjh.17410

Cancer Information Development team

Author

Dr Gillian Horne

Reviewer

Senior Clinical Research Fellow and Honorary Consultant in Molecular Diagnostics and Leukaemia

Beatson West of Scotland Cancer Centre, Glasgow

Date reviewed

Reviewed: 01 July 2025

Next review: 01 July 2028

The language we use

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use plain English
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