What does sensitivity of MRD testing mean?

What does sensitivity of MRD testing mean?

MRD, minimal residual disease is when you try to measure how many cells are left, when there are not many cells left. And so we cannot measure that with standard methods. For instance, we would like to see if is there. If you measure a million cells, can you find the cancer cell there? And that's sort of the level of sensitivity.

It means it means if you have the ability to find one cancer cell among a million cells in the bone marrow, that's a sensitivity of ten to the minus six is what we call it. And if the if you're able to find a cancer cell among 100,000 cells so that that's a bit lower, that's a sensitivity of ten to the minus five.

So the higher the number at the end there is, the more cells you're evaluating and able to find the remaining cancer cells.

Why is it important to know the sensitivity of the MRD test used?

So if they're MRD negative with a ten to the minus five, it means that they examined 100,000 cells and couldn't find the cancer cell. So and that doesn't mean that there are no cancer cells. It just means that within this hundred thousand cells, they were not able to to pinpoint cancer cells. So if you have a MRD negative result and the sensitivity was ten to the minus six, it means that they evaluated a million cells and still couldn't find the cancer cell.

That's better. It doesn't mean that you can have the same result in the same patient, because if there are no cells there, you will be MRD negative, no matter what the sensitivity is. But if the sensitivity is lower, you're less certain of what is remaining there.

Should patients take higher sensitivity tests for MRD ten to the negative six or ten to the negative seventh?

You are not improving prognosis by measuring MRD but you're you're you're picking out the patients who have the best prognosis. So to measure memory doesn't do anything with the prognosis, but it tells you more about what prognosis you are in. And the higher the sensitivity of the test and if the patient is MRD negative, the better the prognosis gets.

And so if you have a group of patients with negative m r d for ten to the minus five, they have a worse prognosis as a group than patients who are negative with a sensitivity of ten to the minus seven. So the better the sensitivity is and MRD is still negative in the particular patient, the better the prognosis is.