Prof. begins development of blood test for appendicitis
Simpler test may reduce usage of more costly and potentially harmful CT scans
April 23, 2010, 4:05 am · Updated April 23, 2010, 12:00 am·
A new blood test for appendicitis under trial at the School of Medicine could eventually replace costly and harmful radiation scans for patients needing immediate diagnoses for abdominal pain.
“Abdominal pain is the most common reason why people come to the emergency department,” said Angela Mills, assistant professor of emergency medicine and the leader of the study at the Hospital of the University of Pennsylvania site, which has approximately 100 of the study’s 800 patients.
She added that actual causes of the pain can range from benign sources to life-threatening ones requiring immediate operations, but physicians rely heavily on testing for diagnosis.
“We’re always looking to decrease some of that testing,” Mills said.
Her study examines whether a simple blood test could potentially replace a CT scan — a costly procedure that uses X-ray imaging to produce cross-sectional images of the body.
While a CT scan is a powerful radiology tool that can diagnose different causes of abdominal pain, it also delivers low doses of ionizing radiation, which is known to increase a patient’s risk of cancer through repeated or large amounts of exposure.
According to Mills, undergoing a CT scan once or twice may not be a problem, but emergency rooms may not always have full information on whether a patient has received one recently. In addition, CT scans take four to five hours to produce results.
Mills cited a culture of over-testing as a possible explanation for the increase in CT scan usage. “With media and education, patients have started to expect a CT scan … they think testing more is better, but they’re not aware of the risks.” Physicians are also likely to rely on the scans because “they’re so readily available, not to mention the medical and legal pressures to produce a concrete diagnosis from testing,” she said.
Studies such as Mills’, however, demonstrate that “people are starting to think about using testing in a judicial way,” she said.
If the study shows that this blood test can accurately diagnose appendicitis, the next step would be to conduct a clinical trial with a rapid blood test that could be conducted at a patient’s bedside, according to Mills. With such a procedure, patients could receive test results in fifteen minutes, she said.
The test requires approval from the Food and Drug Administration before it can be used in hospitals. “It’s hard to guess when, but this blood test probably won’t be in use for at least a few years,” Mills said.