White blood cell count and differential


A white blood cell (WBC) count determines the concentration of white blood cells in the patient's blood. A differential determines the percentage of each of the five types of mature white blood cells.


This test is included in general health examinations and to help investigate a variety of illnesses. An elevated WBC count occurs in infection, allergy, systemic illness, inflammation, tissue injury, and leukemia. A low WBC count may occur in some viral infections, immunodeficiency states, and bone marrow failure. The WBC count provides clues about certain illnesses, and helps physicians monitor a patient's recovery from others. Abnormal counts which return to normal indicate that the condition is improving, while counts that become more abnormal indicate that the condition is worsening. The differential will reveal which WBC types are affected most. For example, an elevated WBC count with an absolute increase in lymphocytes having an atypical appearance is most often caused by infectious mononucleosis. The differential will also identify early WBCs which may be reactive (e.g., a response to acute infection) or the result of a leukemia.


Many medications affect the WBC count. Both prescription and non-prescription drugs including herbal supplements should be noted. Normal values for both the WBC count and differential are age-related.

Sources of error in manual WBC counting are due largely to variance in the dilution of the sample and the distribution of cells in the chamber, as well as the small number of WBCs that are counted. For electronic WBC counts and differentials, interference may be caused by small fibrin clots, nucleated red blood cells (RBCs), platelet clumping, and unlysed RBCs. Immature WBCs and nucleated RBCs may cause interference with the automated differential count. Automated cell counters may not be acceptable for counting WBCs in other body fluids, especially when the number of WBCs is less than 1000/μL or when other nucleated cell types are present.


White cell counts are usually performed using an automated instrument, but may be done manually using a microscope and a counting chamber, especially when counts are very low, or if the patient has a condition known to interfere with an automated WBC count.

An automated differential may be performed by an electronic cell counter or by an image analysis instrument. When the electronic WBC count is abnormal or a cell population is flagged, meaning that one or more of the results is atypical, a manual differential is performed. The WBC differential is performed manually by microscopic examination of a blood sample that is spread in a thin film on a glass slide. White blood cells are identified by their size, shape, and texture.

The manual WBC differential involves a thorough evaluation of a stained blood film. In addition to determining the percentage of each mature white blood cell, the following tests are preformed as part of the differential:

  • Evaluation of RBC morphology is performed. This includes grading of the variation in RBC size (anisocytosis) and shape (poikilocytosis); reporting the type and number of any abnormal or immature RBCs; and counting the number of nucleated RBCs per 100 WBCs.
  • An estimate of the WBC count is made and compared with the automated or chamber WBC count. An estimate of the platelet count is made and compared with the automated or chamber platelet count. Abnormal platelets, such as clumped platelets or excessively large platelets, are noted on the report.
  • Any immature WBCs are included in the differential count of 100 cells, and any inclusions or abnormalities of the WBCs are reported.


This test requires a 3.5 mL sample of blood. Vein puncture with a needle is usually performed by a nurse or phlebotomist, a person trained to draw blood. There is no restriction on diet or physical activity.


Discomfort or bruising may occur at the puncture site. Pressure to the puncture site until the bleeding stops reduces bruising; warm packs relieve discomfort. Some people feel dizzy or faint after blood has been drawn and should be allowed to lie down and relax until they are stable.


Other than potential bruising at the puncture site, and/or dizziness, there are no complications associated with this test.

Normal results

Normal values vary with age. White blood cell counts are highest in children under one year of age and then decrease somewhat until adulthood. The increase is largely in the lymphocyte population. Adult normal values are shown below.

  • WBC count: 4,500–11,000/μL
  • polymorphonuclear neutrophils: 1800–7800/μL; (50–70%)
  • band neutrophils: 0–700/μL; (0–10%)
  • lymphocytes: 1000–4800/μL; (15–45%)
  • monocytes: 0–800/μL; (0–10%)
  • eosinophils: 0–450/μL; (0–6%)
  • basophils: 0–200/μL; (0–2%)



Chernecky, Cynthia C., and Barbara J. Berger. Laboratory Tests and Diagnostic Procedures, 3rd ed. Philadelphia, PA: W. B. Saunders Company, 2001.

Henry, J. B. Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Philadelphia, PA: W.B. Saunders Company, 2001.

Kee, Joyce LeFever. Handbook of Laboratory and Diagnostic Tests, 4th ed. Upper Saddle River, NJ: Prentice Hall, 2001.

Wallach, Jacques. Interpretation of Diagnostic Tests, 7th ed. Philadelphia, PA: Lippincott Williams & Wilkens, 2000.


National Institutes of Health. [cited April 5, 2003] http://www.nlm.nih.gov/medlineplus/encyclopedia.html .

Victoria E. DeMoranville Mark A. Best

User Contributions:

sunee masasso
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Dec 4, 2007 @ 8:20 pm
I would like to know how to compaired WBC automatic analyzer differential and WBC manual differential that it can be as same as in normal case or not? And if I would like to compaired how many and which parameter I can use to compaired?

thank you
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Apr 20, 2008 @ 7:19 pm
It'd be nice if there were some pictures to go along with this article.
Sanjay Chouhan
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Sep 2, 2008 @ 8:08 am
I like the way you gave defination and description and precaution...
I wold like to know how method of counting in laboratry and is any instrument envented for this calculation. Please give me answer..
Thank you,
Sanjay Chouhan
biomedical engg.
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Sep 24, 2008 @ 8:08 am
I would like to know what 962 monocytes mean? Is is considered high for child after long time of cold? Please send me your answer.
Thank you
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Feb 27, 2009 @ 7:07 am
I like this online service. It educates and equip many to better handle challanges in laboratories.

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Jul 5, 2009 @ 10:22 pm
what does it mean the value of wbc is increase? my sister wbc count is 18.35,,, i know its too high. my idea why she got increase wbc because of medications intake. because she suffer cough with whitish to yellowish phlegm and fever. that's why she intake different medications.
francisco gomez-Paris
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Jul 30, 2009 @ 5:17 pm
Interesting but I did not get my question answered. My WBC count is 3.5
I am 74 yrs old is it low high or what. Am I at risk. What is the normal wbc count.

Thank you

Francisco Gomez-Paris
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Aug 13, 2009 @ 11:23 pm
Hi Francisco,

I just got my cbc back from kaiser and i am a 50 year old male. and Kaiser says that normal wbc count is 4.0-11.00/ Yours a little low, but not by much.
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May 31, 2010 @ 4:16 pm
I found the material very well intrpretated ut lacked one thing, the children's normal or abnormal levels of the dfferetail results. My boy had N= 46%, L= 48% Mo = 03% and E=03%, what
would this mean, the Dr simply gave drugs without expaining much
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Jun 3, 2010 @ 10:10 am
my niece white blood cell count is 15,000/μL and she's only 5 years old.will she gonna be okay?.she is in the hospital at the moment.will she gonna be alright?any information is really much appreciated.thank you
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Jul 8, 2010 @ 8:20 pm
My blood test indicates a 2 for META%. The range is (0). What does/could this indicate?
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Aug 15, 2010 @ 4:04 am
Hi Iwant ask about the changing ofthe number of neutrophils to be high than normal range so same to others ( L.M.E.B ) and thanks
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Sep 18, 2010 @ 11:11 am
kindly give me the precautions of increasing the white blood cells
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Nov 26, 2010 @ 3:03 am
I have recently gone through my body check-ups and my white blood cells reading has appreared 11900. Please advise as is this the danger level. Please also advise as how to reduce these cells within rabge (4500-11000).

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Jan 28, 2011 @ 4:16 pm
My son who is 5, just received test results showing a low white count and his lymphocytes were only 1.45 (from I think the normal range of around 6-7.0). He has not been feeling 'well' for a while and has had swollen lymph nodes for over 6 mths. He is pale, has dark circle under his eyes, gets very tired now and has recently been complaining of pains in his legs a lot and nausea/sore belly. He also just can't seem to shake his cold and it keeps returning, whereas before now - he wasn't sick for longer than a day. We've taken him to the GP a few times and they finally just did these blood tests. How concerned should we be and is there anything we can do now while waiting our next appt? Thanks for you help
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Feb 26, 2011 @ 7:07 am
I would like to know if an increased white cell count in a 5day old babies blood is a definite sign of infection.
If not what are the chances of it being an infection and what else could it possibly indicate. Could stress cause the increased level?
Thank you very much,
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Mar 30, 2011 @ 3:03 am
Hello everyone, I would like to know what it means if your white blood cell counts is 2,700? I understand that the normal values / count is btn 4,500 - 10,000. Another question; if someone had a normal white blood cell count, how long will it take to drop down? considering that this person was infected with HIV in last 8 months, how long will take for white cells to drop?

Many thanks
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Jun 25, 2011 @ 4:16 pm
I am 66 years old and recently had a test and my wbc was 11000. Is that high and what do I do to get it down
jennifer criado
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Jul 7, 2011 @ 6:18 pm
i am a 30 year old woman and had a wbc of 15,ooo. i am checking myself every six months for cervical cancer, and also have lyme disease, among 3 different arthritis. my question is...are any of my medical conditions any connection to my wbc.
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Jul 11, 2011 @ 2:02 am
Hi, I am 23 years age,my WBS count test is 1200 cmm, does it means I have leukemia?

harsh patel
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Jul 14, 2011 @ 8:08 am
I would like to know how to compaired WBC automatic analyzer differential and WBC manual differential that it can be as same as in normal case or not? And if I would like to compaired how many and which parameter I can use to compaire
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Sep 23, 2011 @ 2:14 pm
Dear, Dr. this day I brought my 1 year and 9 month kids , and the doctor told me that WBC count of my kids shows 10,700. Please I would like to know what does this mean ? Is it normal range ? , what is a normal range of WBC at this age for male child ? Please help me !
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Nov 11, 2011 @ 1:01 am
i had sex in Feb-2011, in May-2011 i had my HIV tri-dot as Negative. Also my WBC count is 7900,
does that mean i dont have any HIV infection ? ? ?
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Nov 14, 2011 @ 7:07 am
Ok, so i stumbled upon this article by pure chance while i was searching for something else.
Ill try to answer some general questions in easy terms:
-wbc count will Normally Increase incase of an infection, like the common cold for instance, because wbcs fight foreign bodies/germs/antigens. So when antigens enter our body, the wbcs recognise them as foreign and a threat, and they start multiplying to combat it, hence the increase in wbc count.
-wbcs are not just One kind of cell. They have different types which perform different special functions. E.g neutrophils/macrophages are big cells and they literally eat clumps of foreign organisms. Lymphocytes produce antibodies, substances to counter the toxins produced by the antigens.
-the percentages written at the bottom of the article indicate the percentage of a specific cell type. Like neutrophils make up for almost half of our total wbcs while eosinophils and basophils make up very little.

Ok i hope that much helped. And everyone, get well soon. :-)
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Dec 15, 2011 @ 2:14 pm
Ifound this information very helpful, i suffer from autoimmune uveitis, i am taking prednesolone, and cellcept, as i am immunesuppressed i get a lot of infections, my white blood cell count at the moment is 22000,
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Dec 20, 2011 @ 1:01 am
i want to know that what precautions or what to eat for decresing WBC(Neutrophils)?
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Mar 9, 2012 @ 11:23 pm
Jc please have your child checked for leukemia... I don't want to scare you because it very well may be something else but those are some symptoms of leukemia... My son is also 5 ass experiencing don't if those symptoms and sad diagnosed with all leukemia 2 weeks ago
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Jun 15, 2012 @ 4:04 am
My baby only 8 months old. I tested her blood report, WBC count is 22000. is it danger stage ?
please give me feedback.
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Jul 24, 2012 @ 4:16 pm
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Aug 23, 2012 @ 12:12 pm
Hi i made a blood test and everything is in normal range except the lymphocytes the range of my hospital is 1.0-3.0 10^3/ml (me: 4.12) or in % normal range is 25-34% (me:45.4%).. shall i be worry or its ok cause others WBC , PLATELETS AND OTHERS OR OK.
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Aug 27, 2012 @ 1:13 pm
what are the limitations of manual white blood cell count?
hassan kanaan
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Oct 7, 2012 @ 4:04 am
hi i made a blood test and everthing in normal range excepte the lymphocytes the range of my results is 53% ( upper limit ) and the neutrophils count 37% (lower limit) thx you
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Feb 15, 2013 @ 9:09 am
Getting very confused.My doctor said white blood cell count should be 0-10, mine is 19.As i didnt have anything else raised ie rheumatoid - there was no need to worry.I am always very very hot even in winter and suffer from alot of arthritis (osteo) so thought there might be something else going on. Can anyone help!
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Aug 4, 2013 @ 1:13 pm
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Oct 24, 2013 @ 4:16 pm
My 24 y/o daughter has a history of melanoma. Her WBC has always been normal. Today it is 22,000. Should this raise a concern? We are very worried that it is cancer. She has been feeling fatigued. Flu-like symptoms that do not go away.
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Jun 1, 2014 @ 4:04 am
Wonderful this article must be helpful to clarify with the doctors by a patient who may made blood test thanq
raj saini
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Aug 18, 2014 @ 5:05 am
My TLC is 17000 and my age is 71. Pls advise treatment. Thanks
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Sep 5, 2014 @ 2:14 pm
My daughters age is eighteen months and white blood cells are increased to 21 what may be the reason

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