How many normal white blood cells are considered within the normal range

The normal range of white blood cell count for a normal person is 4.0-10.0 × 10 ⁹/L, and the specific value may be affected by age, physiological status, testing methods, disease factors, and medication.

1. Age difference:

Newborns have a higher white blood cell count, reaching 15.0-20.0 × 10 ⁹/L, which gradually decreases to adult levels during childhood. Older adults may have slightly lower than the lower limit of the standard, but should not be lower than 3.5 × 10 ⁹/L. White blood cells in pregnant women can physiologically increase to 12.0-16.0 × 10 ⁹/L, and may further increase during delivery.

2. Physiological fluctuations: After intense exercise, white blood cells can briefly increase by 30% -50%, usually recovering within 2 hours after rest. Post meal testing may result in a 5% -10% increase in results, and it is recommended to take blood on an empty stomach. The circadian rhythm leads to a 10% -15% increase in the afternoon compared to the morning, and there may be a slight increase during the ovulation period of the menstrual cycle.

3. Detection method:

There is a technical error of less than 5% in the detection of different instruments, and the results of venous blood are more stable than those of peripheral blood. Improper use of anticoagulants may lead to pseudo reduction, and sample placement for more than 4 hours can affect accuracy. Partial automatic analyzers have limitations in recognizing abnormal cell morphology and require manual retesting.

4. Pathological factors:

Bacterial infections often have elevated white blood cells accompanied by increased neutrophils, while viral infections often present as normal or decreased. Hematological diseases such as leukemia can increase abnormally, while aplastic anemia can significantly decrease. Autoimmune diseases and splenic hyperfunction can all cause leukopenia.

5. Drug effects:

chemotherapy drugs and immunosuppressants can cause bone marrow suppression and a decrease in white blood cells. Corticosteroids can increase neutrophils and decrease lymphocytes. Antibiotics such as penicillin may cause an increase in eosinophils, while antithyroid drugs may lead to granulocyte deficiency. Maintaining normal white blood cell levels requires ensuring high-quality protein intake, at least 60 grams of animal protein per day, and moderate supplementation of whole grains and green leafy vegetables rich in vitamin B. Regular aerobic exercise such as brisk walking and swimming, 3-5 times a week for more than 30 minutes each time, can enhance immune function. Avoid long-term exposure to benzene based chemicals and ionizing radiation, control work pressure to ensure adequate sleep. When recurrent infections, persistent fatigue, or unexplained fever occur, blood routine should be rechecked in a timely manner. Women of childbearing age should avoid menstrual periods for testing, and medication that may affect results should be notified in advance. It is recommended to undergo regular physical examinations at least once a year, and for those over 40 years old, blood routine examinations can be increased to twice a year.