<s>[INST] Good afternoon. I just got discharged from the hospital. I have bacteremia, proved by culturing. I am on home health care for antibiotic infusion weekly. I am interested in WBC. Apparently, at its peak, my white count was 18.6. What is considered normal, please? . Thank you. Neal Gilbert Centennial, CO [/INST] Hello,The normal number of WBC in the blood is 4,500-10,000 white blood cells/mcL.   These cells play an important role in the immune system by identifying and destroying pathogens ( like viruses, bacteria, or fungi). We  have five major types of white blood cells: basophils, eosinophils, lymphocytes (T cells and B cells), monocytes, neutrophils. A high white blood cell count may indicates:-infection ( like You have),-inflammatory disease ( like rheumatoid arthritis or chronic obstructive pulmonary disease)- leukemia- smoking- stress- allergy, etc.Please note that drugs may also increase WBC counts. These are: corticosteroids, heparin or beta adrenergic agonists.   In my opinion there is no need to worry about your WBC count. 18.6 is high but as you wrote you have bacteremia so this indicate the cause of your high white blood cells count. Hope I have answered your question. If you have any further questions I will be happy to help. </s>