White blood cell count: Leukocytosis is very common with counts more than 10,000 per cubic millimeter and a predominance of polymorphs and immature neutrophils.
Leukocytosis is a common feature of infectious mononucleosis and absence of this should suggest an alternative diagnosis.
The combination of pain, anorexia, leukocytosis, and fever is classic.
It may also present with leukocytosis and anemia, however, the findings are nonspecific.
Conventionally, a leukocytosis exceeding 50,000 WBC/mm3 with a significant increase in early neutrophil precursors is referred to as a leukemoid reaction. … The term leukemoid reaction describes an increased white blood cell count, or leukocytosis, which is a physiological response to stress or infection (as opposed to a primary … ketoacidosis Organ necrosis Hepatic necrosis Ischemic colitis As a feature of trisomy 21 in infancy (incidence of ~10%) As a paraneoplastic phenomenon (rare) Leukemid Leukocytosis … 
Leukostasis is an extreme form of leukocytosis (an excess of white blood cells) that is dangerously symptomatic.
Blood tests: Leukocytosis is seen with a total of around 12000 to 15000 white cells per cubic millimeter. … The minor criteria include the following: Fever Arthralgia Previous history of rheumatic fever Raised Erythrocyte Sedimentation Rate (ESR) or C-reactive protein (CRP) Leukocytosis … 
A complete blood count (CBC) will almost always show leukocytosis, whereas inflammatory parameters - C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and fibrinogen … 
diagnostic criteria are divided into major (Fever ≥ 39°C, joint pain, skin rash, pharyngitis, granulocytosis of ≥ 80%, and glycosylated ferritin fraction of ≤ 20%) and minor (leukocytosis …