Pitfalls

A positive urinalysis does not rule out appendicitis as 30-40% of patients will have abnormal urinalysis
Failure to perform a pregnancy test (urinary or blood) in female patients with abdominal pain can lead to failure to diagnose an ectopic pregnancy with serious consequences
An over-reliance on normal blood tests can result in the diagnosis of appendicitis being missed (1 in 10 patients with appendicitis will have normal inflammatory markers)
Remember that pregnant patients still get appendicitis and may have atypical findings
Atypical presentations and late diagnoses are common in the elderly and children