• Synonym
• Tubes
• Info
• Clinical
• Nl Result
• High Result
• Low Result

Synonym

• CBC
• Blood count
• Hemogram
• Full blood count
• FBC

Tubes

• Lavender (EDTA) top tube
• 5 mL of venous blood

May remain at room temperature for up to 8 hours or refrigerated for 24 hours.

Info

A complete blood count (CBC) is a commonly ordered test that looks at the cells within blood (Red Blood Cells, White Blood Cells, Platelets).

This test gives basic information about the hematologic system, which relates to the following specific items:

• Red Blood Cells (RBCs): These cells carry oxygen from the lungs to the tissues, then return CO2 back from the tissues to be expired by the lungs
• White Blood Cells (WBCs): These cells are involved in immune responses; primarily related to infections
• Platelets: These cells provide clotting functions

• Peripheral smears: Stained blood film examination

The CBC has specific measures that relate to each of these 3 types of cells:

RBC Measures:

1. RBC count: cells/mm³
2. Hematocrit (Hct): measure of RBC mass
3. Hemoglobin (Hgb): measure of hemoglobin mass
4. Mean Corpuscular Volume (MCV): Relates to the size of the red blood cell.
5. Red Blood Cell Distribution Width (RDW): Relates to variability in size present among the RBC's.
6. Mean Corpuscular Hemoglobin Concentration (MCHC)
7. Mean Corpuscular Hemoglobin (MCH)
8. Microscopic examination of RBC's

WBC Measures:

1. WBC count: cells/mm³
2. Differential: Count of the percentage of each WBC subtype (e.g. Neutrophils, Lymphocytes, Monocytes, etc) that are making up the total WBC count.

Platelet Measures:

1. Platelet count: cells/mm³
2. Mean Platelet Volume (MPV): Relates to the size of the platelets

Peripheral Smear:

Often a peripheral smear examination is also performed which includes a visual inspection under a microscope of the blood.

1. Number, size, shape and morphology of RBCs, WBCs, and platelets.
2. Other findings: Parasites, nucleated RBC's, plasma cell, red cell rouleaux, sickle cells, and occasionally circulating carcinoma cells may be noted.

Clinical

Please see the specific section for a detailed explanation of the clinical implications of each test:

• CBC (Red blood cells, Hgb, Hct)
• CBC (MCHC, MCH)
• CBC (Platelets, MPV)
• CBC (WBC's overview)
• CBC (WBC's eosinophils)
• CBC (WBC's lymphocytes)
• CBC (WBC's neutrophils)

CBC (Peripheral Smear)

Conditions where blood smear exam may suggest or confirm the disorder, include:

• Acute leukemia: Blast forms
• Agranulocytosis:
• Decreased neutrophils
• Relative increase in lymphocytes
• Allergic reactions: Eosinophilia
• Bacterial infections:
• Döhle bodies
• Increase in neutrophils
• Increased band forms
• Neutrophil vacuoles
• Chronic lymphocytic leukemia: Absolute lymphocytosis
• Chronic myelogenous leukemia:
• Hypersegmented neutrophils
• Myelocytes
• Promyelocytes
• Compensated acquired hemolytic anemia:
• Erythrocyte agglutination
• Polychromatophilia
• Spherocytes
• Consumptive coagulopathy: Schizocytes
• Elliptocytosis: Elliptocytes
• Hemoglobin C disease: Target cells
• Hereditary spherocytosis:
• Polychromatophilia
• Spherocytes
• Incipient pernicious anemia or folic acid deficiency:
• Hypersegmented neutrophils
• Macrocytosis
• Oval macrocytes
• Infectious mononucleosis: Reactive lymphocytes
• Lead poisoning: Basophilic stippling
• Mechanical hemolysis: Schizocytes
• Oligoblastic leukemia:
• Blast forms
• Pelger-Hüet cells
• Poikilocytosis
• Parasites in the erythrocytes:
• Babesiosis
• Malaria
• Pathologic rouleaux formation:
• Macroglobulinemia
• Myeloma

Nl Result

Each component of the CBC has its own normal values; please see the specific section for these:

• CBC (Red blood cells, Hgb, Hct)
• CBC (MCHC, MCH)
• CBC (Platelets, MPV)
• CBC (WBC's overview)
• CBC (WBC's eosinophils)
• CBC (WBC's lymphocytes)
• CBC (WBC's neutrophils)

High Result

Each component of the CBC has its own high values; please see the specific section for these:

• CBC (Red blood cells, Hgb, Hct)
• CBC (MCHC, MCH)
• CBC (Platelets, MPV)
• CBC (WBC's overview)
• CBC (WBC's eosinophils)
• CBC (WBC's lymphocytes)
• CBC (WBC's neutrophils)

Low Result

Each component of the CBC has its own low values; please see the specific section for these:

• CBC (Red blood cells, Hgb, Hct)
• CBC (MCHC, MCH)
• CBC (Platelets, MPV)
• CBC (WBC's overview)
• CBC (WBC's eosinophils)
• CBC (WBC's lymphocytes)
• CBC (WBC's neutrophils)

References

• Capraro AJ et al. The use of routine laboratory studies as screening tools in pediatric abdominal trauma. Pediatr Emerg Care. 2006 Jul;22(7):480-4
• LabTestsOnline®. Complete Blood Count. [Homepage on the Internet] © 2001-2006. Last reviewed on March 23, 2005. Last accessed on September 13, 2006. Available at URL: http://www.labtestsonline.org/understanding/analytes/cbc/sample.html
• Farrag KA et al. Blood count profile in chronic active hepatitis (C) Egyptian patients. J Egypt Public Health Assoc. 2004;79(1-2):83-94
• Sevastos N et al. Pseudohyperkalemia in patients with increased cellular components of blood.. Am J Med Sci. 2006 Jan;331(1):17-21
• Vroonhof K et al. Differences in mortality on the basis of complete blood count in an unselected population at the emergency department. Lab Hematol. 2006;12(3):134-8