Complete blood count (CBC)

Information about the types and numbers of cells in the blood, especially red blood cells, white blood cells, and platelets is provided in complete blood count (CBC). Your doctor can evaluate symptoms such as weakness, fatigue, or bruising and diagnoses conditions like anemia, infection and other disorders through the results of the test.

Need

The purpose behind complete blood count is as follows:

• Anemia detection
• Infection diagnosis
• Check the severity of blood loss
• Find out the cause behind some symptoms like fatigue, fever, weight loss, or bruising
• Polycythemia Vera diagnosis
• Abnormal value screening before the surgery
• Blood disease diagnosis such as leukemia
• Abnormal bleeding evaluation
• Treatment observation to some kind of drug or radiation treatment
• As a part of routine physical examination

Procedure

The test does not require any kind of preparation. The blood is taken from a vein by inserting needle.

Result

Variation in the normal values of CBC is found from lab to lab. CBC is helpful for doctors to judge the symptoms like weakness bruising, fatigue and the conditions like infection, anemia and many other disorders. Age, sex, type of blood sample and elevation above the sea level also causes variation in the normal values of CBC. Your condition is evaluated by considering all types of values. For instance, your doctor needs your red blood cells (RBC) count, hemoglobin (Hgb), and hemotocrit (HCT) values for the diagnosis of the anemia. However, the red blood cell indices and blood smear is also helpful in the diagnosis of possible anemia. For the assessment of the white blood cell (leukocyte) count, doctor will consider both, number WBC count and WBC differential. To decide if there are too many or very few number of certain types of cells, the total count is multiplied by the number of percentage of that particular cell. Pregnancy may change these blood values. Number of values in each period of your pregnancy is determined by the doctor.
White blood cell count in normal men: 4500-11000/microliter(mcL)³ or 4.5-11.0 x109/liter (SI unites)
Pregnant women:

• 1st trimester: 6,600-14,100/mcL or 6.6-14.1 x 109/L
• 2nd trimester: 6,900-17,100/mcL or 6.9-17.1 x 109/L
• 3rd trimester: 5,900-14,700/mcL or 5.9-14.7 x 109/L
• Postpartum: 9,700-25,700/mcL or 9.7-25.7 x 109/L

White blood cell types (WBC differential)

• Neutrophils: 47%-77%
• Band neutrophils: 0%-3%
• Lymphocytes: 16%-43%
• Monocytes: 0.5%-10%
• Eosinophils: 0.3%-7%
• Basophils: 0.3%-2%

Red blood cell (RBC) count

• Men: 4.6-6.2 million RBCs per microliter (mcL) or 4.6-6.2 x 1012/Liter (SI units)
• Women: 4.2–5.4 million RBCs per mcL or 4.2–5.4 x 1012/L
• Children: 4.6-4.8 million RBCs per mcL or 4.6-4.8 x 1012/L

Hematocrit (HCT)

• Men: 40%-54%
• Women: 37%-47%

Pregnant women:

• 1st trimester: 35%-46%
• 2nd trimester: 30%-42%
• 3rd trimester: 34%-44%
• Postpartum: 30%-44%
• Children: 31%-41%
• Newborns: 44%-64%

Hemoglobin (Hgb)

• Men: 14-18 grams per deciliter (g/dL) or 8.7-11.2 millimoles per liter (mmol/L) (SI units)
• Women: 12-16 g/dL or 7.4-9.9 mmol/L

Pregnant women:

• 1st trimester: 11.4-15.0 g/dL or 7.1–9.3 mmol/L
• 2nd trimester: 10.0-14.3 g/dL or 6.2–8.9 mmol/L
• 3rd trimester: 10.2-14.4 g/dL or 6.3–8.9 mmol/L
• Postpartum: 10.4-18.0 g/dL or 6.4–9.3 mmol/L

Consideration

There are generally no risks in any kind of blood test. You may find bruise, swelling at needle site. Rarely, you may have infection.