Each year, millions of Canadians go through the ritual of seeing their doctor and getting some lab tests. And while they wait anxiously for the results, consider this. A recent Australian study found that in a surprising number of cases, the doctor doesn't bother to check the results.

A study published earlier this month in the Archives of Internal Medicine found that nearly half of all medical tests ordered the day a patient is discharged from hospital aren't even looked at by the doctor caring for the patient. Now you might think that doctors are too busy preparing to send patients home to have time to order tests, but they aren't. Seven percent of all blood tests ordered during a patient's stay in hospital are ordered on the day of discharge. All told, tests ordered on the day of discharge make up 47 percent of tests whose results are not checked by the doctor at the time of discharge.

If you think the doctor eventually gets around to checking the results, you're wrong. Two months following discharge from hospital, most of those lab tests ordered on the day of discharge remain unchecked.

Researchers in this study were only interested in what percentage of tests weren't checked as the patient was preparing to walk out the door to the hospital. They weren't looking to see how patients fared after being discharged, much less trying to figure out whether failing to check lab results had an adverse effect on the patient's welfare. 

That said, me and most of the people I work with in the ER have had the experience of sending a patient home without checking each and every lab test done during the patient's stay. I have no doubt some of those patients had abnormal tests that if checked would have caused us to reverse the decision to send the patient home.

You can wonder rightfully why doctors would tests without checking the results. Sometimes, there may be confusion about who is responsible for looking at the results. That's because it's not uncommon for a patient to be admitted by one physician but seen by several other specialists in consultation.Each consultant orders his or her preferred tests and tracks these while in hospital.

Still, I think I can be blunt in saying that often, the most responsible physician may order tests on the day of discharge but not check the results because they assume they'll be normal because they were normal the day before. That brings me to an important point. I think a lot of the blood tests ordered on the day of discharge are unnecessary and yet they're ordered because the doctor fears being second-guessed by someone else. I also believe there's a misguided belief that justifying an admission to hospital in an era of tight beds means feeling testing patients until the moment they're shown the door.  

The study took place in hospital.You may ask how often do family doctors order tests that are wasted or simply unnecessary. A study of four family practice clinics in the Cincinnati area published in the Annals of Family Medicine showed highly variable response to abnormal test results. Errors resulting from laboratory testing in family medicine have the potential to do serious harm to patients.

Beyond that, there's an epidemic of unnecessary testing - meaning the test should not have been ordered in the first place because it has no clinical value.  The problem has become so acute that various medical groups in the U.S. have banded together to start a project called 'Choosing Wisely'; the aim of the program is get doctors to order fewer inappropriate tests.  Among them: X-rays, CTs and MRIs in patients with back pain, which is largely useless.  Bone-density testing for women at low risk of osteoporosis is another. Doing routine electrocardiograms and stress tests on people at low risk of heart disease are yet another example of unnecessary testing. Although the list was generated in Canada, I believe we can safely say that a similar thing is happening in Canada with medical tests.

I think it's fair game for patients to ask their doctor if each test is necessary. Just making the doctor go through the list with you will reduce unnecessary testing.  At the very least, you should walk out of the office with a list of tests ordered by the doctor so you can ask which ones turned out abnormal.  That should cut down on test results not checked by the doctor.  There are high hopes that electronic medical records will cut down on test results not checked. The study from Cincinnati that I told you about found electronic health records cut down on lab tests not checked by the doctor.  But electronic health records have had an unfortunate side effect.  Instead of reducing unnecessary testing, they seem to encourage it!

When it comes to lab tests ordered by your doctor, never assume that no news is good news.