What to Ask Your Doctor if You’ve Been Diagnosed with MGUS or Smoldering Myeloma 

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma are precursor conditions to multiple myeloma. This is an early disease phase that may develop into cancer. If you have recently been diagnosed with MGUS or smoldering myeloma, you may have a lot of questions. But you may not even know where to begin. 

This guide is designed for the HealthTree community to help you understand what you need to know about your diagnosis. It covers the differences between the precursor stages of myeloma and active disease. It also will help you understand your labs so you can ask the right questions and become an active partner in your care.

At HealthTree, we compiled a series of questions you can download and bring to your next appointment, so the answers are by your doctor, regarding your individual health. 

Download this document to have it in your next appointment and don't miss any questions.

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Comparing MGUS, smoldering, and active multiple myeloma

If you have been told you have a "plasma cell disorder," you are likely at one of three stages. These stages are defined by specific lab values and the presence or absence of symptoms. Doctors use the "CRAB" and "SLiM" acronyms to identify when it is time to move from watching the disease to treating it.

Understanding your diagnosis begins with learning which labs are monitored: the M-Spike, the Bone Marrow Plasma Cell percentage, and whether you have CRAB symptoms or not.

Read more with our in-depth guide Multiple Myeloma Lab Results Explained

What are the "SLiM-CRAB" Criteria?

In 2026, we no longer wait for "CRAB" symptoms (organ damage) to start treatment if a patient has high-risk "SLiM" biomarkers. If you meet any of these, it is considered Active Myeloma.

CRAB: are signs of organ damage

• C - Calcium Elevation: Blood calcium > 11 mg/dL.
• R - Renal (Kidney) Issues: Serum creatinine > 2 mg/dL or creatinine clearance < 40 mL/min.
• A - Anemia: Hemoglobin < 10 g/dL (or 2.0 g/dL below your normal).
• B - Bone Lesions: One or more "lytic" lesions found on CT, PET, or MRI.

SLiM: lab tests that confirm it is a malignant process (malignancy)

• S - Sixty percent: 60% or more plasma cells in the bone marrow.
• Li - Light chain ratio: Involved-to-uninvolved free light chain ratio of 100 or more.
• M - MRI: More than one focal lesion (at least 5mm) found on an MRI scan.

Questions to ask your doctor

If you are an MGUS or smoldering patient, your treatment plan will most likely be active surveillance. This is also called watch-and-wait. This is careful monitoring for detecting changes that may indicate the disease has progressed. If active surveillance is not a good option for you, your care team will take action give treatments to  prevent organ damage, relieve symptoms, and maintain your quality of life.

You can advocate for your right to learn about your health and ask some of these questions in your next appointment. With personalized guidance from your healthcare team, you can feel more at ease with the next steps for you.  

1. What is my exact diagnosis? Is it MGUS? Or is it low-risk smoldering myeloma or high-risk smoldering?
2. What is my current M-Spike and Free Light Chain ratio? How do these compare to my last labs?
3. What is my risk of progression? Ask about the "2/20/20" rule (M-spike > 2, FLC ratio > 20, Plasma cells > 20%).
4. What is my risk status? Even if I don't have CRAB symptoms, do my biomarkers indicate a high risk?
5. What was my bone marrow biopsy result? Specifically, what was the percentage of plasma cells and were there high-risk genetic changes (cytogenetics)?
6. How often do I need labs? Typically every 3-6 months for Smoldering, or 6-12 months for MGUS.
7. What imaging do you recommend? Should I have a whole-body MRI or a PET-CT?
8. Are there symptoms I should watch for?  Do I need to watch for bone pain, extreme fatigue, or changes in urination?
9. Should I be on a bone-strengthening medication (bisphosphonate)? Even if I don't have active myeloma, would a bisphosphonate help?
10. Are there clinical trials for my stage? For high-risk smoldering, would I benefit from early treatment?

Continue reading more Resources for People with MGUS and Smoldering Multiple Myeloma 

Take control of your health with HealthTree

At HealthTree, we believe that tracking your own data is the best way to stay safe. Create a HealthTree account today to upload your lab results. Our tools will automatically track your M-spike and light chains over time, making it easy to spot trends and prepare for your next doctor's visit.

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