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Why we need to track the absolute lymphocyte count (ALC) not white blood cell count (WBC)

Why we need to track the absolute lymphocyte count (ALC) not white blood cell count (WBC)

Here are the six main types of WBCs and the average percentage of each type in the blood:

Neutrophils - 58 percent

Eosinophils - 2 percent

Basophils - 1 percent

Bands - 3 percent

Monocytes - 4 percent

Lymphocytes - 30 percent

The only one that matters for tracking CLL progression are the lymphocytes. These contain B cells, T cells and NK cells, Natural Killer cells.

Tracking white blood cell count (WBC) you have a large number of cell types in that count, which also fluctuate like neutrophils this fact makes the white blood cell count (WBC) very general and rather inaccurate for monitoring CLL progression.

Track your absolute lymphocyte count (ALC) NOT the percentge of lymphocytes, forget white blood cell count (WBC).

When the absolute lymphocyte count (ALC) doubles within 6 months called ...LTD, lymphocyte doubling time...pretreatment talks should be started...


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Thanks for this clarification Chris . There is an information section; “Understanding Your Blood Results” on the CLLSA website at:

Which does explain a lot, also how to calculate your ALC if your results only show Percent Lymphs. Perhaps an important observation, the article points out that roughly only about 5-10% of the total number of WBC are seen in the peripheral blood. Therefor Full Blood Count ,” FBC numbers are useful, but they do not give the whole picture.”

WBC (White Blood Cell count)

White blood cells are produced by the immune system to help defend the body against infection. They and their precursors are formed in the bone marrow and then travel through the blood to various parts of the body. There are several different types of white blood cells, the major ones being neutrophils (also called granulocytes), T-cells and B-cell lymphocytes.

Your FBC report gives the number of white blood cells in the peripheral blood, but it fails to capture the vast majority of them hiding out in the lymph nodes, spleen, bone marrow etc. Only roughly about 5-10% of the total number of WBC are seen in the peripheral blood. FBC numbers are useful, but they do not give the whole picture.


Remember, WBC or white blood cells are many different kinds of cells, the major groups being neutrophils (also called granulocytes) and lymphocytes (which are both B-cells and T-cells).

In CLL, we are interested in following the numbers of lymphocytes. The FBC report typically gives the percentage of the WBC that are lymphocytes. In healthy individuals, there are many more neutrophils than there are lymphocytes (B-cells plus T-cells). As CLL progresses, the absolute numbers of neutrophils may stay the same or even decrease, but the absolute numbers of lymphocytes (B-cells) increase alarmingly. The percentage of the WBC that is lymphocytes therefore also increases as CLL progresses. CLL patients with advanced disease can have WBC and absolute lymphocyte counts as high as 500K or even higher, and their percent lymphocytes can be almost 100%, suggesting that almost all of the WBC are lymphocytes.

The absolute number is much more important than the percentage.

Absolute Lymphs (ALC) Absolute Lymphocyte Count

To get the Absolute lymphocytes number, multiply the WBC by the percent lymphocytes. For example, if the WBC is 30.0, and the lymphocyte percent is 65%, the absolute lymphocyte number is 30.0 X 0.65 = 19.5.

WBC x percent lymphocytes = ALC



Your sample is is the decimal not the percent... but the last formula is wrong...

It should be

ALC = white blood cell count (WBC) times (percent of lymphocytes divided by 100)

Or use the decimal or fraction of lymphocytes NOT the percentage...


From Chaya's site...

WBC is reported at 27.3K and the percentage of these white blood cells that are lymphocytes (“%lymphs”) is reported at 75%. How many lymphocytes are present in this case? What is the ALC?

ALC = WBC x % lymphocytes.

(Remember, 75% expressed as a fraction/decimal is 0.75)

ALC = 27.3K x 0.75

ALC = 20.5K


Here is a calculator for the arithmetically challenged like me!

TLC and absolute lymphocyte count (ALC) are the same...


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thanks for your lesson Percent Lymphs is given as a percentage.I automatically convert that to a fraction in all implementation. . For example 65% =65/100 or 0.65.

In your example 75% = ¾ 0r 0.75

As Chaya mentions ALC = WBC x % lymphocytes.

I posted

WBC x percent lymphocytes = ALC

What's the difference?? ( :

Great links thanks



Was this helpful interview from your CLL LIVE meeting this year. Dr Leclair gave a great overview.

Understanding Your CLL Blood Tests: Immunoglobulin, Complete Blood Counts, Platelets and More

Dr. Susan Leclair explains the meaning behind key tests about which CLL patients are curious.

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I know WE both convert to a fraction but many people miss the decimal conversion part and panic when the absolute lymphocyte count (ALC) is out 2 decimal places...

They miss this note... from Chaya

(Remember, 75% expressed as a fraction/decimal is 0.75)

Its been going on for years...

The correct expression is...

absolute lymphocyte count (ALC) = white blood cell count (WBC) X ( percent of lymphocytes divided by 100)


absolute lymphocyte count (ALC) = % Lymphocytes x WBC / 100

It is the divided by 100 people miss...the conversion of percent to a decimal



OK that makes sense. I have an idea why it may be so hard to see clearly for Brits. ( :

"In the mid 1960s, Britain was different to most other countries by having Roman-style non-decimal currency and measurement units still in use. In Britain, and other Commonwealth countries, it was realised that there were major advantages to be gained by adopting decimal currency and a modern system of decimal measurement units.

While Australia successfully linked both transitions, Britain is remarkable because its highly successful transition to decimal currency was combined with its failure to pull off a similar success in adopting metric units. Indeed when adopting metric, Britain has acted in completely the opposite direction to those policies that made introducing decimal currency such a success.

This divergence is strange when both Britain and Australia saw that the benefits of adopting decimal currency were linked to those of adopting decimal measurement units."

Interesting the UK D-Day (decimilisation day) was February 15th 1971 (I was 8). No sooner had I got to grips with one system, I had to learn and prepare for another. . We kept the penny and had a new unit of 100p not the mille of Europe, the decimal pound, One hundred old pennies before would have been eight shillings and fourpence. We have ended up living with two measurement systems. That don't all follow the 100 rule, maybe that's why I automatically think of percentage as a fraction and a decimal all together and don't automatically remember to portion it in to bits of 100 or identify the calculation?

For Britain there are clear lessons to be learned. Many people have said that Britons are incapable of accepting changes like the conversion to metric units. History shows that this is not the case. Britain has coped well with change when it is well planned and rapid.

It is not too late to learn from the D-day experience. remember 100

Remember, 75% expressed as a fraction/decimal is 0.75


Nick ( :



Thanks for the link and the reply


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