International Staging System (ISS) Calculator
Enter laboratory values to estimate ISS stage for multiple myeloma.
What is the ISS in multiple myeloma?
The International Staging System (ISS) is a widely used method to classify multiple myeloma severity at diagnosis. It uses two blood markers: beta-2 microglobulin and albumin. These biomarkers help estimate overall disease burden and prognosis.
The ISS is simple, fast, and practical in routine care. While treatment decisions are never based on one score alone, ISS remains a core part of initial risk discussion in newly diagnosed myeloma.
ISS stage criteria
| ISS Stage | Criteria | Clinical meaning |
|---|---|---|
| Stage I | Beta-2 microglobulin < 3.5 mg/L and albumin ≥ 3.5 g/dL | Lower-risk biology by classic ISS criteria. |
| Stage II | Not Stage I or Stage III | Intermediate group by ISS. |
| Stage III | Beta-2 microglobulin ≥ 5.5 mg/L | Higher-risk category in classic ISS staging. |
How to use this ISS myeloma calculator
- Enter the most recent serum beta-2 microglobulin value in mg/L.
- Enter the serum albumin value in g/dL.
- Click Calculate ISS Stage.
- Review the stage and brief interpretation.
Always confirm units before entering values. If your report uses different units, convert first to avoid an incorrect stage.
Example
If beta-2 microglobulin is 6.1 mg/L and albumin is 3.2 g/dL, the stage is ISS Stage III because beta-2 microglobulin is at or above 5.5 mg/L.
Why ISS alone is not the whole picture
Modern myeloma care often uses additional systems such as revised ISS (R-ISS), which incorporates cytogenetic abnormalities and LDH. Clinicians also consider kidney function, bone disease, plasma cell burden, symptoms, age, frailty, and treatment response.
In short: ISS is foundational, but not final. Think of it as one important layer in a more complete clinical assessment.
Frequently asked questions
Can this calculator diagnose multiple myeloma?
No. Diagnosis requires formal medical evaluation including labs, bone marrow studies, imaging, and specialist review.
Can ISS stage change over time?
ISS is primarily a baseline staging system at diagnosis. Disease course is usually tracked with serial markers, response criteria, and sometimes updated risk models.
Is a higher stage always a poor outcome?
Not necessarily. Outcomes vary widely with treatment advances, genetics, comorbidities, and depth of response. Discuss your individual prognosis with your oncology team.
Important safety note
This page is for educational support and shared understanding of lab values. It is not medical advice. If you have abnormal results, severe symptoms, or urgent concerns, contact your clinician promptly.