How long do white blood cells survive in the blood stream?

They don't stay in the bloodstream for very long at all. An analogy I often used in lectures and textbooks is that the WBCs in the bloodstream are like commuters on a subway headed to work. Their jobs are performed in the connective tissues, not in the blood. read more

Monocytes spend 10–20 hours in the bloodstream, then leave the blood and transform into macrophages in the connective tissue, where they can live as long as a few years. Lymphocytes live from a few weeks to as long as decades in the connective tissues, as they are responsible for our long-term immunity. read more

White Blood Cells (Type 4: Lymphocyte) Lymphoctyes fall into two major categories: large (e.g. natural killer cells) and small (e.g. Helper T cells, Cytotoxic T cells, and B cell). Natural killer cells, which destroy both tumors and cells infected with viruses, have a life span of up to two weeks. read more