How are MRD tests collected - are they run off of blood or bone marrow samples?

Are MRD tests done from blood or bone marrow samples?

So is MRD tested more on the blood or the bone marrow? And it really does depend. In general, MRD testing is more optimally performed on the bone marrow. We're able to get a better sample generally and we're able to look for smaller amounts of MRD if we use a bone marrow sample. However, there are some different types of MRD tests and it depends on the specific subtype of leukemia. In certain subtypes of leukemia, it's acceptable to do blood testing. In many practices, often we may alternate bone marrow testing and blood testing, obviously because bone marrow testing adds an additional layer of complexity to the testing as opposed to just a simple blood test.