Three general guidelines are used to classify the severity of neutropenia based on the ANC (expressed below in cells/µl):
Mild neutropenia (1000 <= ANC < 1500): minimal risk of infection
Moderate neutropenia (500 <= ANC < 1000): moderate risk of infection
Severe neutropenia (ANC < 500): severe risk of infection.Each of these are either derived from laboratory tests or via the formula below:
ANC = 
  
    
      
        
          (
          %
          n
          e
          u
          t
          r
          o
          p
          h
          i
          l
          s
          +
          %
          b
          a
          n
          d
          s
          )
          ×
          (
          W
          B
          C
          )
        
        
          (
          100
          )
        
      
    
    {\displaystyle (\%neutrophils+\%bands)\times (WBC) \over (100)}

Treatment
A fever, when combined with profound neutropenia (febrile neutropenia), is considered a medical emergency and requires broad spectrum antibiotics.
Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria, bacterial fragments and immunoglobulin-bound viruses in the blood. People with neutropenia are more susceptible to bacterial infections and, without prompt medical attention, the condition may become life-threatening (neutropenic sepsis).Neutropenia can be divided into congenital and acquired, with severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) being autosomal dominant and mostly caused by heterozygous mutations in the ELANE gene (neutrophil elastase). Neutropenia can be acute (temporary) or chronic (long lasting). The term is sometimes used interchangeably with "leukopenia" ("deficit in the number of white blood cells").Decreased production of neutrophils is associated with deficiencies of vitamin B12 and folic acid, aplastic anemia, tumors, drugs, metabolic disease, nutritional deficiency and immune mechanisms. In general, the most common oral manifestations of neutropenia include ulcer, gingivitis, and periodontitis. Agranulocytosis can be presented as whitish or greyish necrotic ulcer in oral cavity, without any sign of inflammation. Acquired agranulocytosis is much more common than the congenital form. The common causes of acquired agranulocytosis including drugs (non-steroidal anti-inflammatory drugs, antiepileptics, antithyroid and antibiotics) and viral infection. Agranulocytosis has a mortality rate of 7–10%. To manage this, the application of granulocyte colony stimulating factor (G-CSF) or granulocyte transfusion and the use of broad-spectrum antibiotics to protect against bacterial infections are recommended.