Examining patients and taking a medical history are more useful to hospital doctors in diagnosing patients than high-tech scans, according to a study.

Tests such as CT scans and ultrasounds add to hospital bills, but doctors said that such tests given right after patients showed up in emergency rooms only helped with diagnosis in roughly one of three cases, the study -- published in the Archives of Internal Medicine -- said.

There is also research showing that the radiation from multiple CT scans might increase the risk of cancer over the long term.     

To see whether such scans were really helpful, researchers led by Ami Schattner of Kaplan Medical Center in Rehovot, Israel, followed all the patients who showed up at the emergency room of a teaching hospital and were subsequently admitted.

"Basic clinical skills remain a powerful tool, sufficient for achieving an accurate diagnosis in most cases," Schattner and his colleagues wrote.

"Physicians may count more on their clinical faculties when making decisions about patients."     

Over about two months, Schattner and his colleagues observed 442 consecutive patients. Each was separately examined by two doctors, a resident and a senior physician, who also asked patients about past health problems.

Both doctors had access to results from all routine tests, including blood and urine analysis, and any extra scans that had been done when the patient first got to the emergency room.

The researchers later looked at how accurate the clinicians were in their decisions, compared to the final diagnoses patients were given during or after their hospitalisation. They also asked the doctors what factors they relied on most when diagnosing each patient.

Both clinicians made the correct diagnosis between 80 and 85 percent of the time. Only about one in six patients had extra testing -- mostly CT scans, usually of the head -- done in the emergency room. The rest just had simple blood, urine or heart tests.     

But even for the patients who did have extra scans, the doctors said the results helped to make a diagnosis only about one-third of the time.

Instead, patient history alone or history plus a physical exam were most important to a doctor's correct diagnosis in almost 60 percent of cases. When basic tests were included, they were the basis of more than 90 percent of correct diagnoses along with the history and exam.

"The doctoring process is still a personal communication between the patient and the clinician," said Matthew Sibbald, a cardiologist at the University of Toronto who wasn't involved in the study.     

"As much as we want to... rely on the technology, it's not the technology that helps us make a diagnosis," he told Reuters Health. - Reuters