Roundup Edition
Monoclonal Gammopathies:
A Round Up
Dr. Astha Thakkar · March 2026
Over the past several weeks, we've worked our way through the full spectrum of plasma cell disorders — from the incidentally discovered, usually-benign MGUS all the way to active multiple myeloma requiring treatment.
Before moving on to new territory, it's worth pausing to collect these posts in one place. Think of this as your reference index — whether you're reviewing a concept, sharing with a colleague, or encountering one of these diagnoses for the first time.
The plasma cell disorder spectrum
| MGUS | Smoldering Myeloma | Multiple Myeloma |
Plasma Cell Disorder — Stage 01
MGUS: Monoclonal Gammopathy of Undetermined Significance
MGUS is the most common plasma cell disorder — often discovered by accident on routine bloodwork, causing no symptoms, and requiring no treatment. What it does require is understanding: who has it, what the risk of progression looks like, and how to tailor surveillance based on immunoglobulin subtype. We covered MGUS in two posts, starting with the fundamentals and then going deeper into why IgG, IgA, and IgM subtypes each tell a meaningfully different story.
Plasma Cell Disorder — Stage 02
Smoldering Multiple Myeloma: The Middle Ground
Smoldering myeloma occupies one of the most clinically nuanced spaces in hematology — more abnormal cells than MGUS, but no end-organ damage yet. The key questions: how do we risk-stratify using the 2/20/20 rule, who should be watched vs. treated, and what does evolving trial data tell us about early intervention for high-risk patients? This post breaks down the diagnostic criteria, the risk stratification models, and the shifting treatment landscape.
Plasma Cell Disorder — Stage 03
Multiple Myeloma: Diagnosis, CRAB, and the SLiM Criteria
Active multiple myeloma is defined not just by the number of clonal plasma cells in the marrow, but by evidence that the disease is causing harm — or is at very high risk of doing so. This post covers the full diagnostic criteria, including the classic CRAB features and the 2014 IMWG update that introduced the SLiM biomarkers. We also covered a clinical case that illustrates how myeloma doesn't always follow the textbook script.
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More coming soon.
Future posts will go deeper into myeloma treatment, POEMS syndrome, AL amyloidosis, Waldenström macroglobulinemia, and more. Subscribe to get each new issue delivered straight to your inbox.
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