Q: I had my routine blood check up. RBC is 4.29 and WBC is 11700. The report says mild leukocytosis present. What does that mean? I am 43 years old.

A:The normal total leukocyte (white blood cells) count varies with the age of a person. It also has a diurnal cycle i.e. counts vary during a 24 hour day. Normally they range from 4000 to 10,000 per ml in an adult. Leukocytosis is an increase above the accepted normal range of total leukocytes. Usually only one type of cell is responsible for this increase, but there may be a simultaneous increase in several cell types. The counts may go up due to an increase in any component of the white cells i.e. neutrophils (called neutrophilia), lymphocytes (called lymphocytosis), monocytes (called monocytosis), eosinophils (called eosinophilia) or basophils (called basophilia). This can be judged by a differential leukocyte count. The range of each of these cells also varies with the age of an individual. There are numerous causes for increases in neutrophils, lymphocytes etc. The degree of leukocytosis depends upon several factors like its cause, severity of the infection, resistance of the body, localisation of the inflammatory process (greater neutrophilic leukocytosis is produced by a localised disease process rather than a generalised one) and modification by treatment. Physiological leukocytosis refers to a total leukocyte count above the normal, without the association of any known disease process. It is usually associated with conditions that result in a release of the hormone adrenaline (epinephrine), with the immediate mobilisation of neutrophils that have marginated in small blood vessels or extra-vascularly in several organs, including the lungs, spleen, lymphatic tissue and haematopoietic bone marrow. These then enter the circulation and increase the total count. All cell types can increase but the trend is towards neutrophilia (increase in neutrophils) without a left shift. This may occur due to strenuous exercise, excitement, fear, apprehension, or pain, convulsive seizures etc. In contrast, pathological leukocytosis is secondary to infection (localised or generalised), tissue necrosis from any cause (infarction, burns, gangrene, neoplasms), metabolic (uraemia, acidosis), chemical intoxication, insect venom, allergic reactions, acute haemorrhage or haemolysis and malignancy (leukaemia). Your husband needs to be examined, as one does not treat an abnormal laboratory result but an individual who is unwell.