Blood-Based MRD Testing in Myeloma: What Patients Should Know

Blood-based minimal residual disease (MRD) testing may help doctors monitor multiple myeloma with fewer bone marrow biopsies. However, these blood tests are still less sensitive than bone marrow MRD testing. They are not yet considered a replacement. In a recent HealthTree webinar, myeloma expert Dr. Benjamin Derman explained how these tests work and how they may fit into future myeloma care. 

Why MRD testing matters in myeloma

MRD testing looks for very small amounts of remaining myeloma cells after treatment. Doctors use MRD testing to better understand treatment response and relapse risk.

Today, most MRD tests use bone marrow biopsies. Bone marrow testing remains the most sensitive and reliable method available. 

But many people with myeloma wonder whether blood tests could provide similar information. This matters because bone marrow biopsies can be uncomfortable. They may also need to be repeated over time. 

The blood-based MRD tests researchers are studying

Researchers are studying several blood-based MRD methods in myeloma. These tests look for myeloma cells, myeloma DNA, or abnormal proteins in the blood. They include:

• Peripheral blood flow cytometry
• Next-generation flow testing after plasma cell enrichment
• Blood-based next-generation DNA sequencing, including clonoSEQ
• Circulating tumor DNA (ctDNA)
• Cell-free DNA
• GenoPredicta
• Soluble BCMA
• Mass spectrometry tests, including Mass-Fix, EXENT, EasyM, and M-InSight

Early studies suggest some mass spectrometry tests may closely match certain bone marrow MRD results. This may be especially true after long-term negative findings. 

Mass spectrometry tests measure unique “fingerprints” of myeloma proteins in the blood. They detect lower myeloma levels than standard blood work. Researchers are still studying how to use these tests in routine care. 

Blood MRD testing still has limitations

Current blood MRD tests are generally less sensitive than bone marrow MRD tests. Even if blood MRD tests are negative, myeloma cells may still remain in the bone marrow.

However, studies discussed during the webinar showed that positive blood MRD tests may help identify people at higher risk of earlier progression. This information may help doctors decide when closer monitoring or treatment changes are needed. 

Questions still remain about how to use these tests

Researchers are still learning how often blood MRD testing should be performed. They are also studying how results should guide treatment decisions.

Some myeloma specialists already use MRD results when discussing treatment changes or stopping therapy. Others prefer more long-term research before changing care based on blood MRD findings alone.

Blood MRD testing may help people who cannot tolerate frequent bone marrow biopsies. It may also help people with non-secretory myeloma, where standard protein testing is less useful. 

Questions to ask your doctor

• Is MRD testing a part of my care?
• Is blood-based MRD testing appropriate for my type of myeloma?
• Which blood MRD tests are available at my treatment center?
• Are any blood MRD tests covered by my insurance?