Activity 2: Differential White Blood Cell Count



Differential White Blood Cell Count

Do this activity as a table team.

Most of you will never do differential white blood cell counts on the job, but you should know how counts can be used to diagnose infections. You should suspect bacteria if the neutrophils are high, viruses if lymphocytes are high, parasitic worms if eosinophils are high (though allergy is a possibility too), and AIDS if lymphocytes are low. You should know that high band counts suggest acute bacterial infections. Bands are replacement neutrophils just entering circulation. Their nuclei are band-shaped unlike the segmented nuclei of mature neutrophils, or “segs”. You should know that atypical lymphocytes are an important indicator of infectious mononucleosis. These cells are transformed T lymphocytes responding to B lymphocytes which are infected with Epstein-Bar virus. Atypical lymphocytes are irregularly shaped because the cytoplasm is frequently indented by the surrounding red blood cells. You can see pictures of all these WBCs on the next page.

Practice what you just read by filling in these blanks.

High neutrophils suggest infections.

High lymphyocytes suggest infections.

High eosinophils suggest or .

Low lymphocytes suggest .

High bands suggest acute infections.

Atypical lymphocytes suggest .

Note that the counts and percentages of each type of WBC shown on these patients’ pages are slightly different from the percentages given in the

Allen/Harper Lab Manual.

Picture Key

Seg neutrophil Band neutrophil

[pic] [pic]

Lymphocyte Atypical lymphocyte

[pic] [pic]

Monocyte

[pic]

Eosinophil Basophil

[pic] [pic]

Report for Patient Number _______ (Write your patient’s number.)

Identify all 100 white blood cells in your patient’s two-page blood smear. Keep track of your count by putting marks next to the WBC names below as you count. Total up the marks and write the totals in the percentage column. Counts are percentages because you counted a total of 100 cells. Indicate whether or not percentages are normal by writing yes or no. Normal percentages are given in parentheses. PLEASE DO NOT WRITE ON THE TWO-PAGE BLOOD SMEAR. WE NEED IT FOR OTHER CLASSES.

Count Percentage Normal?

Segs _________ (50-65%) ________

Bands _________ (0-5%) ________

Normal

Lymphocytes _________ (15-40%) ________

Atypical

Lymphocytes _________ (0-1%) ________

Monocytes _________ (0-10%) ________

Eosinophils _________ (0-5%) ________

Basophils _________ (0-2%) ________

Next, decide whether your patient is normal, has parasites, has a bacterial infection, has mononucleosis, or has AIDS.

High eosinophils often indicate parasites.

High neutrophils with high bands indicate acute bacterial infection.

High lymphocytes plus atypical lymphocytes suggest viral mononucleosis.

Low lymphocytes suggest AIDS. Keep in mind that other WBCs will

seem high when lymphocyte percentage is low.

Now share your diagnosis with the other members of your table team. Put your heads together and answer all of the questions on the next page.

Patient 1’s diagnosis:

Patient 2’s diagnosis:

Patient 3’s diagnosis:

Patient 4’s diagnosis:

Patient 5’s diagnosis:

(Your table team did not have a Patient 5 if there were only four of you.)

The developed world has a lower incidence of parasites than the developing world. If your patient has a high percentage of eosinophils, what would be a good follow-up question to ask?

The immune system usually increases lymphocytes when fighting viral infections. Why then are lymphocytes low in HIV patients?

Which one of patients 1-4 most likely got infected during surgery? Explain your answer.

What concern should you have if the patient with mononucleosis is a high school football player?

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