Last summer, a 55-year-old teacher from Dover, Mass., had a CT scan that showed a suspicious mass on her left ovary, but the test wasn’t conclusive. So her gynecologist ordered an MRI, which the patient, who did not want her name published, had on a Wednesday. The lab technicians told her it would take a day or so to get the results.

Worried that the mass might be ovarian cancer, the patient called her gynecologist on Thursday. And Friday. “I couldn’t reach her. I kept getting her secretary,” the woman recalled. It wasn’t until Monday that she got the results, which suggested the mass might not be cancerous after all.

The woman, who may change gynecologists because of the incident, was furious that it took so long to get an answer that had supposedly been ready for days. “The waiting was difficult, trying to keep positive and optimistic when you know that something is growing inside you,” she said.

Waiting for tests and test results is often the most frustrating, anxiety-provoking part of medical care. And there is less and less excuse for it.

“There is no reason why a test result cannot be offered to the physician within 24 hours,” said Dr. Howard Forman, vice chairman of diagnostic radiology at the Yale University School of Medicine and director of Yale’s MD-MBA program. Not just routine blood tests, he said, but X-rays, CT, and MRI scans, the domain of radiologists.

Five years ago, there was a good reason for delays in radiological testing: A patient’s old films, used for comparison purposes, had to be retrieved physically from the files. “Now, most departments are digital, or could be if they chose. We have instant retrievability of prior images, so that is no longer an excuse,” said Dr. Forman. “A radiology report should be provided within 24 hours in 99% of cases.”

Moreover, voice-recognition technology today dramatically shortens the time it takes a radiologist to finalize a report. “A CT scan these days takes 15 minutes to do, an MRI might take 30 to 45. In a complicated case, it could take up to half an hour to read the scans,” said Dr. David Levin, former chairman of the radiology department at Thomas Jefferson University in Philadelphia.

In the past, doctors had to dictate a report, have it typed up, edit it, then mail it to the referring doctor, which took several days. Now, computers process the radiologist’s voice as he looks at the image and create an instant written report.

“We have the technology to make the readings and even digital images available to physicians automatically within seconds of the images being read by a radiologist,” Dr. William M. Tierney, director of the division of general medicine and geriatrics at the Indiana University School of Medicine, wrote in an e-mail.

But things often bog down, partly from sheer volume. A study at Brigham and Women’s Hospital showed that the average primary care doctor gets 240 test results a day, though a complete blood workup may include 20 tests, said John Glaser, vice president and chief information officer at the Partners HealthCare system, of which Brigham and Women’s is a member.

Modern technology has also provided other ways to shorten the time it takes for patients to get results.

Beth Israel Deaconess Medical Center, for instance, has an Internet-based system called PatientSite that allows patients to log on and, in most cases, see certain test results, even before their regular doctor does.

“If you are a patient, you have much more interest in knowing these test results than the doctor does,” said Dr. Daniel Sands, one of the creators of PatientSite. To avoid unnecessarily alarming patients, though, the site does not include results from CT scans or pathology reports that might indicate cancer, however.

PatientSite is “exemplary,” said Pat Rutherford, vice president of the Institute for Healthcare Improvement in Boston, a nonprofit health organization. “Information in the patient’s chart, including medical test results, isn’t ours, it’s the patient’s. Yet historically, we’ve treated patients as if we are giving them a window on our work, as opposed to us having a window on their life.”

Other medical systems are following suit, to varying degrees. Harvard Vanguard Medical Associates has a system called MyChart that allows patients to see test results after their doctor has reviewed them.

In California, the Palo Alto Medical Foundation system allows patients access to their electronic medical records through www.pamfonline.org, though for lab tests and radiology, the doctor always sees the report before it is made available to the patient, said Dr. Peter Tang, chief medical information officer.

With mammograms, a highly anxiety provoking test for many women, hospitals vary in how fast they communicate results to women. At Mass General, radiologists try to get reports out within 24 hours to 48 hours, admittedly “a long time, psychologically,” said Dr. Daniel Kopans, director of breast imaging. But that time is necessary, he said, to enable two radiologists to read each X-ray for maximum accuracy.

Boston’s Faulkner Hospital’s breast imaging and diagnostic center gives women same-day results and has both a radiologist and a computer scan each X-ray, said Dr. Norman Sadowsky.

To be sure, some waiting is inevitable because of biology, not bureaucracy. To ascertain what virus or bacteria has invaded a patient’s system, for instance, lab technicians must grow the germs in cell culture, which can take several days. PAP tests for cervical cancer can take weeks because the test, which involves an expert looking carefully at slides under the microscope, is so labor-intensive. Flow cytometry on white blood cells to check for leukemia can take a day or two because cells have to be tagged and counted, said Dr. David Keren, a pathologist who heads the Warde Medical Laboratory in Ann Arbor, Mich.

And in some cases, waiting is necessary to give a patient’s body time to respond to treatment. Dot Chainey, a 57-year-old painter who lives in the Mohave Desert in California, is currently waiting anxiously for a CT scan to see if a drug she took to treat her recurring non-Hodgkin’s lymphoma worked. “I can’t deal with it,” she said. “I’ve tried yoga, I’ve tried to distract myself as best as possible,” she said. “This is my life, waiting for the day to come for the CT scan.”

In many ways, this kind of uncertainty is “the worst disease in the world,” said Dr. Tom Delbanco, a general internist at Beth Israel. “The not-knowing can be worse than knowing the worst.”

Ms. Foreman is a lecturer on medicine at Harvard Medical School. Her columns are available at www.myhealthsense.com.