What Are Normal Blood Count Numbers and What Do They Mean?

Normal red blood cell counts are between 3.9 and 5.7 million cells per microliter, white blood counts range from 3,500 to 10,500 cells per microliter, and platelet counts range between 150,000 to 450,000 cells per microliter, says Mayo Clinic. Blood count numbers help doctors diagnose infections and other disorders.

A complete blood count is useful for patients experiencing symptoms such as fatigue and weakness that may be due to problems such as infections or anemia, says WebMD. Red blood cells are important in transporting oxygen throughout the body. For men red cell counts between 4.32 and 5.72 million cells per microliter are normal, and counts between 3.9 and 5.03 million cells per microliter are normal for women, according to Mayo Clinic. Hemoglobin provides red blood cells with oxygen, and normal counts are between 135 and 175 grams per liter for men and between 120 and 155 liters for women.

Hematocrit levels tell doctors the volume of red blood cells in the blood, says WebMD. These levels should be between 38.8 and 50 percent for men and between 34.9 and 44.5 percent for women, reports Mayo Clinic. White blood cell counts between 3,500 and 10,500 cells per microliter are normal for both genders. White blood cells play an important role in defending the body from infection, says WebMD, and elevated levels can indicate an active infection. For both men and women platelets, which help blood clot, should be between 150,000 to 450,000 cells per microliter.