Normal blood counts fall within the range that has been established by testing healthy men and women of all ages. The cell counts are compared to those of healthy individuals of similar age and sex.

Leukopenia is a general term for having too few white blood cells, covering all five main types: neutrophils, lymphocytes, ...

A typical platelet count range can change with age. Platelet counts may fluctuate due to natural vascular aging, changes in bone marrow tissue, and altered blood plasma makeup. Platelets, or ...

A high red blood cell count can occur for many reasons, including excessive cell production, changes in blood volume, or underlying medical conditions. Sometimes, the cause is unknown. Erythrocytes, ...

Human immunodeficiency virus (HIV) attacks CD4 cells, which are a small part of the white blood cells. In acute HIV, white blood cell count may drop slightly but still look “normal.” A white blood ...

Dear Dr. Roach: I have been confused about what normal blood pressure is for me (or anyone). I know there are some issues on what normal is today, but let us say that normal is 120/80 mm Hg. Does this ...