If you are concerned about receiving a blood test result with a high white blood cell (WBC) count (leukocytosis), be reassured that the most common reason for a high WBC, is a high lymphocyte or neutrophil count, most often from an infection or inflammation, not cancer. A low count can also be due to infection.
What can cause a high lymphocyte count or “lymphocytosis”?
Most commonly, lymphocytosis may result from:
- A recent infection,
- An inflammatory condition like arthritis,
- A severe illness or accident,
- A reaction to a medicine, or
- Even as a result of stress.
Is the Diagnosis of CLL Made With a Lab Test for Lymphocytes?
Having high lymphocytes does not necessarily mean cancer. (My emphasis) If there is no other cause for leukocytosis and your level remains higher than normal, another test that may be needed is a flow cytometry. This test is used to diagnose CLL and determine if the extra lymphocytes in the blood are CLL cells or not. (They may be due to an even less common blood cancer, some of which are closely related to CLL and treated with the same drugs - Neil)
Further information on lymphocytosis and CLL (registration required) can be found in this easily readable Blood Basics introductory article from Patient Power: patientpower.info/chronic-l...
If you are diagnosed with CLL, because CLL cells are included in your lymphocyte count, measuring your absolute lymphocyte count (not the percentage - see later*), provides a far more accurate measure of how much CLL is in your blood than measuring your WBC count.
What Do High and Low Neutrophil Counts Mean?
Neutrophils are the immune system’s first line of defense. They rush to the site of an infection or injury in the body to attack invading pathogens and call in more immune cells for backup. They are the most abundant type of white blood cell (WBC) circulating in the blood.
Low Neutrophils "Neutropenia"
Having a low level of neutrophils (neutropenia) does not cause symptoms on its own. However, some of the common causes of neutropenia, such as bacterial and viral infections, can cause illness, including fever, sore throat, and fatigue. These infectious (sic) are typically short-term, and when the infection clears, the level of neutrophils usually returns to normal.
(Note that if you have a very low neutrophil count, typically under 1.0 or 1,000 (most US Labs), then you are at high risk of infection - see reference (3) at the end of this post for tips on how to protect yourself.)
High Neutrophils "Neutrophilia"
High neutrophils means the body is under stress. Infection, inflammation, stress, and vigorous exercise can cause increased neutrophil levels. In response to these insults, neutrophil reserves in the bone marrow (and spleen - Neil) are released. These spikes are generally short-term.
The full Blood Basics article (again, registration is required) on neutropenia and neutrophilia can be found here: patientpower.info/what-do-h...
More information on CLL/SLL, which, importantly is classified as an orphan disease as it's a relatively rare cancer, can be found in our Pinned Posts section: healthunlocked.com/cllsuppo...
Two of our introductory posts about CLL/SLL, the most common Non-Hodgkin's Lymphoma diagnosed in adults, are;
1) CLL for dummies
healthunlocked.com/cllsuppo...
(This is the first in a series of 'dummies' posts by cajunjeff . Here's the index to the rest: healthunlocked.com/cllsuppo... )
2) Newly diagnosed with Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma - CLL/SLL or just found us? This post is for you!
healthunlocked.com/cllsuppo...
As mentioned above, neutropenia (low neutrophils) puts you at increased risk of possibly severe infection, which brings us to;
3) With a CLL diagnosis, knowing more about your immune system could save your life!
healthunlocked.com/cllsuppo... Here, you'll find some very important tips on what to do if you are severely neutropenic, including references on how to recognise febrile neutropenia, which requires Emergency (ER) attendance to determine if you need urgent IV antibiotic treatment.
If you are diagnosed with CLL/SLL, always remember that this is a Chronic blood cancer; it is quite unusual to need treatment soon after diagnosis. In fact a significant percentage of those diagnosed with CLL/SLL never need treatment - it can be many years, even a decade or more before treatment may be required. The older 'chemo' treatments are also being replaced with gentler, more effective targeted therapies. Joining this 21,000+ strong international CLL Support community is probably the last thing you wanted to do, but here you'll find shared experiences, along with evidence based management and treatment options for CLL/SLL. You'll be kept up to date with the latest means by which you can increasingly expect to live out a normal life expectancy. There's more about our community in our About post: healthunlocked.com/cllsuppo...
* Note that it's very important to appreciate that your WBC count is made up of five different white blood cell types, the most numerous types being your neutrophils and lymphocytes. The absolute counts (typically indicated with a "#") for each white blood cell type are usually listed in the "Differential" section of your Complete Blood Count or Exam (sometimes called Full Blood Count, Examination or Picture). Hence the abbreviations CBC, CBE, FBC, FBE and FBP are interchangeable. Please ignore the percentage results in your differential, (typically indicated with a "%"); it's the absolute counts - and which count is causing the high WBC, that matters.
Neil
Illness for two months, low white blood count just at 1. 
Leukaemia Care Updated Patient Information - Richter's Syndrome in Chronic Lymphocytic Leukaemia 
Diagnosed at 10 am Today
High white count, need advice 
