RE: Clarification on 3-log and PCRU

[Guest guest]

At 02:37 PM 2/18/07 -0500, you wrote:

>What is the difference betwen PCRU and 3-log reduction .

>

>Is it means then when you are at -3.7 log , you are not completely

>undetectable .

>

>Thanks .

>

>Emile

># 527 Zavie's List

Hi Emile,

When you are PCRU, it means that they did not detect ANY ph+ cells in the

test. One important thing to know is what is the sensitivity of the test,

it could be only 10,000.......or more typically 100,000 cells and then also

1 million cells.

When they say you have a certain log reduction, it means you must still

have some detectable cells. And the truth is.....even when you are PCRU,

you still have some leukemia cells (they just were not picked up on the

test that was run). This is why you will relapse if you stop taking the

drug you are on....because there are still leukemia cells.

C.

[Guest guest]

Hi Emile,

This is a little bit of a difficult concept to get.

PCRU should mean undetectable. The problem is that even though the test

reports your result as PCRU or undetectable, there are still some Leukemia

cells left in your body.

This depends on how sensitive the PCR test is that they are running at the

hospital where you get your blood tested at.

Most labs can detect when you have achieved a 3 log reduction in you CML

cells. Many labs can detect up to a 4 log reduction in the CML cells. But

beyond this, very few labs can detect a 5 log or greater reduction in the

CML cells.

Lets face it, if there were no CML cells left in our body, we would be cured

and wouldn't have to take any medication for it.

It turns out that once you have attained a 3 log reduction there is very

little chance that you will ever relapse with your CML as long as you

continue to take Gleevec (or one of the newer drugs). I believe the odds are

less than 0.5%.

I know that in the hospital that I go to they can measure up to a 4 log

reduction. Once past this level they simply say that the PCR result is

greater than a 4 log reduction. It could be 4.1 or 5 or 6. They just cannot

tell with the equipment that they are using.

Now to answer your two questions.

1. PCRU is better than a 3 log reduction.

2. Yes.

Zavie

[ ] Clarification on 3-log and PCRU

What is the difference betwen PCRU and 3-log reduction .

Is it means then when you are at -3.7 log , you are not completely

undetectable .

Thanks .

Emile

# 527 Zavie's List

[Guest guest]

Thank's and Zavie .

As usual , we always found the information we need on this list .

Take care

Emile