Final answer:
Leukemoid reaction is an elevated white blood cell response, often mirroring leukemia but not due to cancer, with leukocytosis being a classic lab finding. Leukocytosis occurs in response to infections, inflammations, or other stress factors, like severe burns, prompting a rise in white blood cells.
Step-by-step explanation:
The term leukemoid reaction refers to an extreme reaction of the white blood cell count occurring in response to certain conditions such as infections, inflammation, malignancy, or stress (e.g., severe burns). In this reaction, there is a significant increase in white blood cells, resembling leukemia, but it is not due to cancer. A classic lab finding associated with a leukemoid reaction is leukocytosis, which is an elevated white blood cell count, often found with increased numbers of immature white cells, known as a left shift.
It's important to note that leukocytosis is a response to factors such as chemical attractants released by pathogens and signals from nearby injured cells. For instance, a patient with a severe burn would exhibit leukocytosis due to the body's immune response to tissue injury and possible infection, whereas an individual with severe allergy symptoms would likely have increased activity of a particular leukocyte type that responds to antihistamines.