A measurement of the quantity of white blood cells (WBCs) in the blood is the absolute neutrophil count (ANC). The core of our immune system is made up of WBCs. WBCs called neutrophils aid in the elimination of any viruses and germs that enter our bodies. Infections, a wide range of inflammatory conditions, and some myeloid neoplasms all result in higher levels of it. Chemotherapy, poisons, bone marrow replacement (for instance, for metastatic tumours or granulomas), myelodysplastic syndromes, autoimmune diseases, and congenital diseases can all cause neutropenia (lower neutrophil count). The patient's risk of infections is typically determined by the level of neutropenia.