MonocytesMonocyte count
White cells that clear debris and become tissue macrophages.
Monocytes are large white blood cells that circulate briefly before moving into tissues, where they mature into macrophages: the cells that engulf debris, dead cells and microbes, and help direct the wider immune response.
It matters because they reflect longer-running processes rather than the immediate response. The count tends to rise with chronic infections, recovery from acute illness and inflammatory conditions.
In practice monocytes are one line of the white cell differential and are read as a proportion of the whole rather than in isolation.