Meaning of CD38 Result of Dim ?

[Guest guest]

Hello.

In my first CLL genetics markers testing I received a CD38 expression result

of " Dim " (as opposed to " Negative " , " Moderate " , or " Bright " ).

What does this mean in a ~quantitative~ sense?

Does it indicate (rather vaguely in a quantitative sense) the number (i.e.,

the proportion) of cells with the CD38 antigen, ~OR~ does it indicate (also

rather vaguely) the relative amount of CD38 present on each cell? Or...?

How does " Dim " translate to a percentage? How can I know how it compares to a

" 20% expression " figure, for example?

The testing was done by Genzyme in NYC.

Thanks for any clarification offered...

Fred

[Guest guest]

" dim " compared with " bright " or " negative " are quantitative measures of

expression. The " dim " refers to a low-level of expression. Since the

expression is detected by the amount of fluorescence on a cell that results from

a particular antibody, it is seen as being " bright " or " dim " .

With regard to the significance with CD38, dim or bright are both positive. The

prognostic value of CD38 has only been studied in terms of positive versus

negative, never examined with regard to intensity of expression. Positive cases

are those cases where > or =30% of the CLL cells express CD38, while negative

are those where <30% express CD38. On some reports the numbers may express the

CD38 of all cells analyzed, and not the CLL cells. You cannot use those numbers

to make the determination. One would have to look at the raw data and make the

determination. (Which is what the flow cytometrist does.)

Rick Furman, MD

>

> Hello.

>

> In my first CLL genetics markers testing I received a CD38 expression result

> of " Dim " (as opposed to " Negative " , " Moderate " , or " Bright " ).

>

> What does this mean in a ~quantitative~ sense?

>

> Does it indicate (rather vaguely in a quantitative sense) the number (i.e.,

> the proportion) of cells with the CD38 antigen, ~OR~ does it indicate (also

> rather vaguely) the relative amount of CD38 present on each cell? Or...?

>

> How does " Dim " translate to a percentage? How can I know how it compares to a

> " 20% expression " figure, for example?

>

> The testing was done by Genzyme in NYC.

>

> Thanks for any clarification offered...

>

> Fred

>