Workup

Laboratory Studies

Complete blood cell count
Studies consistently show that 80-85% of adults with appendicitis have a WBC count greater than 10,500 cells/mm³. Neutrophilia greater than 75% occurs in 78% of patients. Fewer than 4% of patients with appendicitis have a WBC count less than 10,500 cells/mm³ and neutrophilia less than 75%.
Dueholm et al, in 1989, further delineated the relationship between WBC count and the likelihood of appendicitis by calculating likelihood ratios for defined intervals of the WBC count.