Which laboratory test is critical to evaluate for signs of infection in abdominal pain cases?

The complete blood count (CBC) is crucial for evaluating signs of infection in cases of abdominal pain because it provides important information about a patient's immune response. An elevated white blood cell (WBC) count, particularly with a shift toward immature neutrophils (a "left shift"), can indicate the presence of an infection or inflammation. In the context of abdominal pain, a CBC can help healthcare providers identify conditions such as appendicitis, diverticulitis, or other intra-abdominal infections.

While the basic metabolic panel (BMP) assesses electrolyte and metabolic status, and serum electrolytes are important for evaluating physiological function, neither directly indicates infection. Urinalysis can detect urinary tract infections, but it does not provide a comprehensive overview of abdominal conditions unrelated to the urinary system. Thus, the CBC is the most relevant test for assessing potential infectious processes related to abdominal pain.