International Staging System for Multiple Myeloma: Clinical Guide

Overview

Assigns multiple myeloma stage from serum beta-2 microglobulin and albumin.

Clinical Significance

ISS stage I requires beta-2 microglobulin 5.5 mg/L.

When to Use

• Use as structured clinical decision support when the required data are available and reliable.

How It Is Calculated

• The displayed variables are combined using the published equation, decision rule or weighted point system.

Interpretation

• ISS stage I requires beta-2 microglobulin <3.5 mg/L and albumin ≥3.5 g/dL; stage III requires beta-2 microglobulin >5.5 mg/L.

Worked Example

Enter verified patient data in the displayed units; MedicalC applies the published model.

Limitations

• Risk and classification tools can be misapplied outside their validated population.
• Missing, estimated or non-contemporaneous data may materially change the result.

Clinical Pearls

• Document the inputs, units, date and clinical setting with the result.
• Use serial scores only when the same instrument and measurement method are used consistently.

Common Mistakes

• Using the tool without confirming entry criteria.
• Using approximate or incorrectly converted values.
• Treating a prognostic score as a standalone treatment decision.

References

1. Greipp PR et al. J Clin Oncol. 2005;23:3412-3420. — Primary or supporting reference for the implemented model.