Bec, I'm no doctor or expert, but as a former lab technician I believe a lab test, specifically a CBC [Complete Blood Count] can help a doctor diagnose an ailment such as appendicits (if I remember correctly, the White Blood Cell [WBC] count will generally be elevated with a increased neutrophil population).

Way back, the oldest daughter complained of lower abdominal pain and described it as more intense than cramps. It was hard to tell if this was just a bad case of the 'monthly' cramps, or something else. A CBC was performed and the WBC count was increased. Other testing performed by the doc pointed to appendicitis. NOTE: I'm no doctor or expert, and a CBC may not explain a medical ailment. If you feel you or a loved one are ill, please seek medical attention immediately.