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:
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 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.
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
thank you
Sunee
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.
Thank you
Diana
Thanks!!
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
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.
would this mean, the Dr simply gave drugs without expaining much
Thankyou.
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
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,
James.
Many thanks
Thanks
does that mean i dont have any HIV infection ? ? ?
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. :-)
i want to know that what precautions or what to eat for decresing WBC(Neutrophils)?
please give me feedback.
Pls reply...
my son is 14 years old his white blood cells counting is 2,600. is it any dangerous and what is the correct range of WBC for a male child .please give me advice
Eosinophils are also increased.
Age 57 ,wbc count 14700/cu mm is high or low and this is due to why?
Is it ok ? Or is it needful to get hospitalized for few days ?? How can I reduce WBC count at normal level? Thanks
Total leucocyte count is 15300
Neutrophils 79%
My body is paining and I feel like iching if I touch it its becoming little more bigger wt 2 do
Is it normal or not? If not, what should I do. Please suggest me.
My WBC count is 12200 in march 2016 & 11200 in Dec 2014 & 8600 in 2013 and I am now 40 years of age please advise
Iam satish from Vizag. Ihave one small problem
In my blood wcb. Cell count 3,900.
And platelet. Count1.5 lakhs if it this what is problem? If any problems?
So plz give me clarification
I am constantly having Lymphocytes count high around 44% of 7600 total WBC count for past 4+ years, but my white blood cell count is Normal (Normal in morphology,maturity and distribution).
Please do suggest me whats happening
Is a danger stage ?.and how many months i was recorvered from this problems
My baby girl of w year old having cervical lymphidities and little sweling on right of belly.last day i have CBC test and it show 15400 wbc ..is it easily treated and ends up with medication antibiotic or any thing serious?
red cell count is 5.42
total wbc is 12800
neutrophil is 74
is this report is harmful