Neutrophils

Some laboratories use 1.7 to 7.5; people of African or Middle Eastern ancestry commonly sit lower in the general population; use the range your lab printed.

Neutrophils are the most numerous type of white blood cell and the first to arrive when there is a bacterial infection or tissue damage. This is the absolute number of them in a given volume of blood, worked out from the total white cell count and the differential.

It is part of the full blood count differential. Doctors watch it during infections, after chemotherapy and with medicines that can lower it, because a low neutrophil count leaves the body less able to fight bacterial infection.

• Bacterial infection
• Inflammation from any cause
• Smoking
• Steroid medicines
• Stress, strenuous exercise and the hours after surgery
• Pregnancy
• Some bone marrow conditions

• Viral infections
• Chemotherapy and some other medicines, including some antibiotics, antithyroid tablets and clozapine
• Low vitamin B12 or folate
• Autoimmune conditions
• Bone marrow conditions
• An enlarged spleen
• Inherited lower counts, common in people of African or Middle Eastern ancestry

• Exercise or stress shortly before the test raises it for a few hours
• Steroid tablets raise it as an expected effect
• A lower count with no ill effect is common in the general population in people of African or Middle Eastern ancestry
• Small dips during and just after a viral illness recover on their own

No fasting needed. A count taken during an infection is best repeated once well.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.