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Photo of a person getting blood work The ABCs of common medical tests
 
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One thing we all have in common is that at one time or other our doctors are going to send us for medical tests—and some are going to be required regularly. Something many of us share is nervousness about some of these tests.

But many of these tests have some things in common as well: they can help prevent disease, they can provide an early diagnosis of disease that increases the chance of successful treatment and they aren't half as bad as they sound! Understanding that may be all the encouragement most of us need.

What follows is some basic information about some of the more common tests. Some preparation for these tests will differ for pregnant women or people who have other conditions or diseases. Talk to your healthcare provider.

Bone density test

If your healthcare provider has reason to believe that you are at higher risk for osteoporosis or that the thickness of your bones needs to be monitored, you might be sent for a bone density test. This test uses a type of x-ray to measure how dense, or thick, your bones are by calculating how much calcium and other minerals are present.

No preparation is needed, and the test is quick and painless. You will likely be asked to lie on a table while the x-ray scans parts of your spine, hips and possibly other parts of the body.

Generally, this test is recommended for Canadians aged 65 and over or those with specific risk factors for osteoporosis.

Complete Blood Count (CBC)

It sounds pretty intensive, but if your healthcare provider wants to take a CBC—which is typically standard during a complete physical—it won't involve anything more than one needle prick to the arm so the lab technician can withdraw a few vials of blood. The blood is sent off to a lab, where it is used to assess your general blood health—number of white and red blood cells, amount of haemoglobin and so on—to diagnose diseases and conditions such as anemia, as well as acute and chronic infections.

Blood samples are also used to measure levels of glucose in the blood and to screen for diabetes. A glucose test may involve blood being taken from the arm or by a prick of the finger. Some glucose tests involve fasting, some involve drinking a sweetened drink prior to the test and some do not require any change in eating or drinking.

Blood tests are also used to check blood cholesterol levels to determine whether the levels in your blood are within healthy range. Unhealthy cholesterol levels are a risk factor for heart disease.

CT scanning

A CT (computerized tomography) scan, sometimes called a CAT scan, is an incredibly useful tool that provides health professionals with a multidimensional view of the inside of the body. It can detect early problems such as cancer and cardiovascular disease, including stroke, with its special x-rays that take pictures from many different angles. The images are then reassembled by a computer to form a detailed picture of your interior.

Preparation for the test depends on what area you are having scanned. Some CT scans require nothing special, while others require drinking water or taking a contrast material by mouth, IV or enema to give the radiologists a clearer picture. You can wear comfortable clothes but you will be asked to remove jewellery and other metal objects.

The machine is a large square with a hole in the centre. The table you lie on slides back and forth through the hole while a rotating x-ray takes the pictures. You will hear noises, you may be asked to hold your breath from time to time, and you will be alone in the room but in constant contact with the radiologist, who will be speaking to you over intercom. The procedure itself is painless and typically fairly quick, between 5-30 minutes. Illustration of a notepad and pen


Echocardiogram

A simple echocardiogram is a completely painless ultrasound (soundwaves) test used to get a two-dimensional, cross-sectional picture of your heart.

No preparation is needed; you will wear a gown and lie on a table to be examined. Electrodes are attached with sticky paper to your chest and shoulder to record the results of the test. The technician will then put cool gel on the chest and use the ultrasound wand, or transducer, to move around the area and take measurements of the heart chambers. To get various views of the heart, you will be asked to shift positions.

Fecal occult blood test (FOBT)

The Canadian Cancer Society recommends that men and women age 50 and over have a fecal occult blood test (FOBT) at least every two years. The FOBT is a test to find blood in the stool that is not visible to the naked eye. Three separate stool samples are collected by a person in their own home and then brought to a laboratory for analysis. FOBT blood testing helps identify small growths or polyps early before they become cancerous. The presence of blood does not necessarily mean cancer – it could be caused by a non-cancerous condition. If blood is found, more testing is necessary to find out if it was caused by cancer.

Colorectal cancer is one of the most detectable and, if found early, most treatable types of cancer, but is currently Canada's second biggest cancer killer after lung cancer.

Those who are at higher than average risk of developing colorectal cancer should discuss an individual plan of monitoring with their healthcare provider.

Follow-up for a positive test could include a colonoscopy, double contrast barium enema (an x-ray of the large intestine) and sigmoidoscopy.

Mammography

A mammogram is a low-dose x-ray used specifically to screen for, or detect, breast diseases in women. A screening mammogram may be recommended by your healthcare provider to determine whether your breasts are healthy. Mammograms also help doctors detect and diagnose early breast cancer in women who may be experiencing abnormalities.

Women between 50-69 years should have a mammogram every two years. If you are under age 50 or over 69 and are at a higher risk for breast cancer, you should discuss with your healthcare provider when mammography may be appropriate for you. Women over age 40 should have a clinical breast examination by a trained health professional at least every two years.

Mammograms are not painful—for some people, in fact, they are absolutely painless—but they can cause discomfort if your breasts are sensitive. Whenever possible, try to schedule a mammogram for a less tender time of the month—ideally, about a week after your monthly period has ended. Do not wear deodorant the day of the test or, if you do, you will be asked to remove it as it can interfere with the images. You will be asked to put on a hospital gown.

The images are taken while you stand up, pressed against the mammography machine with one breast firmly compressed by a plastic paddle. Typically, two images are taken of each breast, and your position will be readjusted between each one. If you do experience discomfort, it will only last a few seconds; if your discomfort is causing you distress, let the technician know and the compression will be eased up. After the test, which takes 20 minutes or so, you will be asked to wait while the pictures are checked for clarity. If further images or tests are required, the clinic or your health care provider will contact you.

Magnetic Resonance Imaging (MRI)

To most people, the MRI may seem similar to the CT scan: both are large machines with tubes or tables going through a hole in the middle; both are scans, sometimes involving the use of contrast material, and both provide an excellent view of the inside of the human body so are great diagnostic tools.

But, unlike the CT scan, the MRI machine is actually a giant magnet, with pulses of energy that go through the part of the body to be scanned bit by bit and which are then assembled into two-dimensional images or three-dimensional models.

The tube for the MRI is much smaller than the CT scan and is not a favourite test of people who suffer from claustrophobia. You should discuss this with your healthcare provider and/or the radiologist beforehand, as this is a common problem.

You will have to lie perfectly still, sometimes for long periods of time, while the MRI does its job. Nothing metal will be allowed into the scanning room with you, as it can be pulled directly into the opening of the magnet. That includes metal in the body as well: you will be screened for dental or orthopaedic implants, pacemakers and so on, and some people with such implants will have to have another kind of test. The test is also very noisy, and some centres allow patients to use earplugs to help block the noise.

Pap smear

According to the College of Family Physicians of Canada, if every woman had a regular Pap smear test, 90% of all cases of cervical cancer could be prevented. That's a pretty compelling reason for every woman who has had sex or has reached the age of 18 to keep tests up to date—that is, every one to three years depending on your test results and your doctor's advice, for the course of your life.

To take a Pap smear—which is a sample of cells from the cervix, the opening of your uterus—your doctor or healthcare provider will ask you to lie on your back on the examination table with your knees bent and open. An instrument called a speculum is inserted to keep the vagina open so the doctor can gently swab the cervix for a sample. To make the test most accurate, you should not use vaginal douches and contraceptive jellies or creams for 48 hours before the test and you should not have intercourse 24 hours prior to the test.

There is no pain during a Pap test; some women may find it a little uncomfortable, but the test only takes a couple of minutes—and the more relaxed you are, the faster and more comfortable it will be. The sample is then sent to a lab and if the cells are normal, your Pap test is negative; if abnormal cells are found—which can be for any number of reasons—your doctor or healthcare provider will discuss next steps with you.

Medical tests are a sometimes a necessary part of life, and their value—preventing and detecting diseases early—is beyond measure.

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  Date published: April 1, 2007
  BulletThis article was prepared by Nora Underwood for Canadian Health Network. Nora Underwood is a journalist living in Toronto.

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