Why we should use numbers (#) not percentages (%) for white cells - Dr Susan Leclair

Why we should use numbers (#) not percentages (%) for white cells - Dr Susan Leclair

One of the problems of having an orphan disease like CLL, is that while standard processes in the medical system work well for the majority of patients, sometimes they don't work for us and can be positively misleading. That's the case with white blood cell differentials - the breakdown of individual white blood cells that constitutes the White Blood Cell (WBC) Count. Knowing how many actual neutrophils and lymphocytes you have in your blood is very important for two reasons:

1) To correctly measure the rate at which your CLL is progressing, you need to measure your Absolute Lymphocyte Count increase NOT your WBC increase; you can't get your ALC increase from comparing percentages.

2) To know to what degree you are at risk from bacterial infections, you need to know your absolute neutrophil count; the percentage of neutrophils in your blood sample can't tell you that.

I've explained this many, many times, but perhaps Dr Susan Leclair can explain this better than me. So here's her post to the CLL ACOR list from last Friday: (Note Susan uses 'granulocyte' in place of 'neutrophils'; it's another name for the most common white blood cell in healthy people and they are varyingly called polymorphonuclear cells, PMN's, polys, granulocytes, segmented neutrophils or segs, just to confuse matters further).

Date: Fri, 16 Sep 2016 22:24:53 -0400

From: Dr Susan J Leclair

Subject: Re: Lymph% and #

The percentage lymphocyte count is the number you get from evaluating a total of 100 white cells. It is a great way to evaluate the qualitative aspects of the cells. But because it is a random 100, it is difficult to determine if the increased percentage of a specific cell line is due to a real increase or a corresponding decrease in another cell line. For example, is the 90% granulocyte count due to an increase in granulocytes or a decrease in lymphocytes?

Th absolute lymphocyte count is the actual counting of lymphocytes in a specific volume of cells. It can not be misinterpreted.

Why is this important? For folks with CLL, a percentage differential can give the appearance that you have few to no granulocytes because of the increase in lymphocytes. But the absolute granulocyte (neutrophil) count is good enough to protect you from pesky infections.

For example

Total WBC.______% lymphs.____%grans.____Abs. Lymph.____Abs Grans/(Neuts)

5.00.____________ 80.__________20.________4.0.__________1.6

There is no increase in lymphocytes but there is a significant decrease in granulocytes.

Total WBC.______% lymphs.____%grans.____Abs.lymph._____Abs. Grans/(Neuts)

10.00.____________ 8.0._______ 20.________8.0.________2.0

There is a significant increase in lymphocytes but the granulocytes(neutrophils are minimally acceptable.

When CLL becomes more active in the marrow, it is often accompanied by a decrease in platelets and soon to follow a decrease in red cells.

Susan Leclair

Neil

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  • Neil,

    You were very clear and helpful.

    Rick

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