MGUS Progression Risk Calculator
Use this tool to estimate progression risk for monoclonal gammopathy of undetermined significance (MGUS) based on the widely used Mayo Clinic 3-factor model.
Non-IgG isotypes count as one risk factor.
> 1.5 g/dL counts as one risk factor.
Outside 0.26 to 1.65 counts as one risk factor.
What this MGUS risk calculator estimates
This page estimates long-term progression risk from MGUS to a plasma-cell disorder (such as multiple myeloma or related conditions) using the classic Mayo Clinic 3-factor approach. It helps summarize lab findings into a practical risk category so patients can have a clearer discussion with their doctor.
How the score is calculated
The 3 Mayo risk factors
- Non-IgG isotype (for example IgA or IgM)
- M-protein > 1.5 g/dL
- Abnormal serum free light chain ratio (below 0.26 or above 1.65)
Each factor contributes one point. The total (0 to 3) maps to a risk category. In general, more risk factors mean higher progression risk over time.
Interpreting your category
- 0 factors: Low risk
- 1 factor: Low-intermediate risk
- 2 factors: High-intermediate risk
- 3 factors: High risk
Commonly cited 20-year progression estimates are approximately 5%, 21%, 37%, and 58% for 0, 1, 2, and 3 factors, respectively. Some publications also report lower competing-risk adjusted values (about 2%, 10%, 18%, and 27%), reflecting that not everyone is followed for a full 20 years.
Inputs explained
1) Isotype (IgG vs non-IgG)
Isotype comes from your serum immunofixation report. In this model, non-IgG MGUS carries more progression risk than IgG MGUS.
2) M-protein concentration
M-protein (also called M-spike) is measured on serum protein electrophoresis. A value greater than 1.5 g/dL is one risk point in this model.
3) Free light chain ratio
The kappa/lambda free light chain ratio is a marker of clonal imbalance. Ratios outside 0.26 to 1.65 are considered abnormal for this score.
How this helps with follow-up planning
Risk tools can support shared decisions about how often to repeat labs and when hematology follow-up should occur. Typical conversations include:
- How often to repeat CBC, creatinine, calcium, SPEP, and free light chains
- Whether imaging or bone marrow studies are needed now or later
- What symptoms should trigger immediate reassessment
Symptoms that should not be ignored
Contact your clinician promptly if new warning signs appear, such as:
- Persistent bone pain or fractures
- Unexplained fatigue, anemia, or recurrent infections
- Kidney problems, swelling, or reduced urine output
- High calcium symptoms (constipation, confusion, excessive thirst)
- Unintentional weight loss or night sweats
Important limitations
MGUS risk is individualized. This calculator does not include every biologic variable and cannot replace specialist interpretation. Lab methods, reference ranges, kidney function, and coexisting conditions can all affect results. Also, this tool is intended for MGUS and may not apply to smoldering myeloma, active myeloma, AL amyloidosis, or other plasma cell disorders.
Bottom line
A structured MGUS risk estimate can make your follow-up plan clearer and less overwhelming. Use the result as a conversation starter with your hematologist, not as a final diagnosis.