complete blood count

1. CBC
Complete blood count

2. OUTLINE
1. Definition
2. Causes
3. Diagnosis
4. Risk factors
5. Treatment
6. Nursing role

3. WHAT IS COMPLETE
BLOOD COUNT?
 A complete blood count (CBC) is a test that
counts the cells that make up your blood: red
blood cells, white blood cells, and platelets. Your
doctor may order a CBC as part of a routine
checkup or to:

4. • Check for anemia, a condition that causes you to
have fewer red blood cells than usual
• Find out if you have another health issue or to explain
symptoms like weakness, fever, bruising, or feeling
tired
• Keep an eye on a blood condition
• See how medications, medical conditions, or treatments
like chemotherapy are affecting your blood

5. HOW IS A CBC DONE?
 If the CBC is the only blood test you are having, you
can eat and drink like you usually would. Your part of
the test is simple and takes just a few minutes. A nurse
or lab tech will take a sample of blood by putting a
needle into a vein in your arm. Afterward, you can leave
and get back to your routine. They will send the blood
to a lab for review.

6. WHAT DOES A
CBC MEASURE?
 The test can tell your doctor a lot about your overall health. It
measures:
•White blood cells (WBCs). These help your body fight germs. If you
have too many of them, it could be a sign of inflammation, infection, a
medical reaction, or another health condition. If it’s low, you could be at a
higher risk for infection. A medication, a viral infection, or a bone marrow
disease could also cause a low count.

7. •Red blood cells (RBC). These deliver oxygen throughout your
body. They also help carry carbon dioxide. If your RBC count is too
low, you may have anemia or another condition.
•Hemoglobin (Hb or Hgb). This is the protein in your blood that
holds oxygen
•Hematocrit (Hct). This test tells how much of your blood is made up
of red blood cells. A low score may be a sign that you don’t have
enough iron, the mineral that helps your body make red blood cells. A
high score could mean you’re dehydrated or have another condition.

8. •Mean corpuscular volume (MCV). This is the average
size of your red blood cells. If they’re bigger than usual,
your MCV will be higher. That could happen if you have
low vitamin B12 or folate levels. If your red blood cells
are smaller, you could have a type of anemia.
•Platelets. These help your blood clot.

9. CBC RESULTS
 When you get your report, you’ll see two columns:
a “reference range” and your results. If your results are inside
the reference range, they’re considered normal. If your results
are higher or lower than the reference range, they’re abnormal.
Mild anemia is one of the most common reasons your results
might be off.

10.  Each lab has different ways of studying
your blood. So the reference range will depend
on the lab that handles your blood tests. It’s also
based on things that can affect your blood like
your age, your sex, and how high above sea level
you live.
In general, the reference ranges are:

11. •White blood cells: 4500 to 11,000 cells per microliter
(cells/mcL)
•Red blood cells: 4.5 million to 5.9 million cells/mcL for
men; 4.1 million to 5.1 million cells/mcL for women
•Hemoglobin: 14 to 17.5 grams per deciliter (gm/dL)
for men; 12.3 to 15.3 gm/dL for women
•Hematocrit: 41.5% to 50.4% for men; 35.9% to 44.6%
for women
•Mean corpuscular volume: 80 to 96
•Platelets: 150,000 to 450,000 platelets/mcL

12. WHAT ELSE MIGHT MY CBC
TELL ME?
Your doctor might order more results to learn whether
you have an illness or blood condition, including:
• Mean corpuscular hemoglobin (MCH). This test
tells how much hemoglobin is in your typical red blood
cell.
• Mean corpuscular hemoglobin concentration
(MCHC). This measures the concentration of
hemoglobin in a certain amount of blood.
• Red cell distribution width (RDW). This shows
how your much your red blood cells vary in size.

13. • Reticulocyte count. This test measures the
number of new red blood cells in your body.
• Mean platelet volume (MPV). This result gives
the average size of the platelets in your blood.
• Platelet distribution width (PDW). This shows
how much your platelets vary in size.
• White blood cell differential. There are five
types of white blood cells: basophils, eosinophils,
lymphocytes, monocytes, and neutrophils. This test
shows how many of each kind you have.

14. WHY DO HEALTHCARE
PROVIDERS ORDER CBCS?
CBCs are an important part of a yearly physical exam. Providers also order
CBCs to monitor the side effects of some prescription medications.
Your provider may order a CBC to:
• Detect abnormalities in your blood that may be signs of disease.
• Diagnose or monitor many different disorders, conditions and
infections.
• Evaluate your overall health.
• Rule out conditions, disorders and disease.
• Monitor various blood diseases.

15. -Healthcare providers use complete blood
counts to manage disease and help you stay
healthy. With one sample of blood, CBCs can
help screen for hundreds of disorders,
conditions and infections. A CBC can detect
conditions early, sometimes before you have
symptoms, so treatment can start as soon as
possible. CBCs are an essential tool in
maintaining good overall health.

16. WHEN IS A CBC
PERFORMED?
 You may need a CBC if you have symptoms such as:
• Bruising or bleeding.
• Fatigue, dizziness or weakness.
• Fever, nausea and vomiting.
• Inflammation (swelling and irritation) anywhere in the body.
• Joint pain.
• Problems with heart rate or blood pressure

17. WHAT ARE THE RISKS OF
THIS TEST?
A CBC is a safe, common test. There are
no risks involved, and your provider only
removes a small amount of blood. Rarely,
some people feel a little faint or lightheaded
after a CBC.

18. WHAT DOES A CBC
DETECT?
A CBC blood test can help your provider diagnose a wide
range of conditions, disorders, diseases and infections,
including:
•Anemia (when there aren’t enough red blood cells to carry
oxygen through the body).
•Bone marrow disorders, such as myelodysplastic syndromes

19. •Disorders such as agranulocytosis and thalassemias and sickle
cell anemia.
•Infections or other problems that cause abnormally low white
blood cell count or high white
blood cell count.
•Several types of cancer, including leukemia and lymphoma.
•Side effects of chemotherapy and some prescription
medications.
•Vitamin and mineral deficiencies

20. NURSING
CONSIDERATIONS
1. Explain test procedure. Explain that slight discomfort may be felt
when the skin is punctured.
2. Encourage to avoid stress if possible because altered physiologic
status influences and changes normal hematologic values.
3. Explain that fasting is not necessary. However, fatty meals may
alter some test results as a result of lipidemia.

21. 4. Apply manual pressure and dressings over
puncture site on removal of dinner.
5. Monitor the puncture site for oozing or
hematoma formation.
6. Instruct to resume normal activities and diet.

22. WHAT ARE THE BENEFITS
OF THIS TEST?
A CBC gives your provider a picture of your
overall health. Using a small amount of blood, a
CBC can help detect hundreds of conditions,
disorders and infections. It allows your provider to
monitor your health, screen for disease and plan and
adjust treatment.

23. WHEN SHOULD I KNOW
THE RESULT OF THE TEST?
Results are usually ready within a few days.
Sometimes it only takes 24 hours to get results. Your
provider will contact you to explain the results and
discuss next steps. If your blood cell counts are outside
of the normal range, your provider may order follow-up
tests.

24. WHAT SHOULD I EXPECT
AFTER THE TEST?
You’ll have some gauze and a bandage on your
arm, secured with tape. Your arm may be a little
sore for a few hours. You may develop a small
bruise where your provider inserted the needle.

25. WHEN SHOULD I CALL MY
DOCTOR OR NURSE?
 your provider will review the results
of your CBC with you. If you have
questions about the results, call your
provider.

26. Thank you