According to a report by Bolandparvaz and colleagues, the urinary 5-hydroxyindoleacetic acid level could be an early marker of appendicitis. The rationale for such measurement is related to the large amount of serotonin-secreting cells in the appendix. The investigators noted that levels increased significantly in acute appendicitis, decreasing when the inflammation shifted to necrosis of the appendix. Therefore, such a decrease could be an early warning sign of perforation of the appendix.
Studies consistently show that 80%-85% of adults with appendicitis have a WBC count > 10,500 cells/µL. Neutrophilia > 75% occurs in most patients. Less than 4% of patients with appendicitis have a WBC count < 10,500 cells/µL and neutrophilia < 75%.
CRP is an acute-phase reactant synthesized by the liver in response to infection or inflammation and rapidly increases within the first 12 hours. CRP has been reported to be useful in the diagnosis of appendicitis; however, it lacks specificity and cannot be used to distinguish between sites of infection.
Urinalysis may be useful in differentiating appendicitis from urinary tract conditions. Mild pyuria may occur in patients with appendicitis because of the relationship of the appendix with the right ureter. Severe pyuria is a more common finding in urinary tract infections. Proteinuria and hematuria suggest genitourinary diseases or hemocoagulative disorders.
Read more about the workup of appendicitis.
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Cite this: Richard H. Sinert. Fast Five Quiz: Appendicitis Diagnosis and Treatment - Medscape - Mar 13, 2019.