Common Screening Tests

Sometimes a physical examination of your body is not enough to tell your doctor the full condition of your health. In such cases the doctor may order a number of common screening tests. Blood tests and urinalysis help the doctor find out if all of the components of your blood or urine are at normal levels. Scanning techniques such as X rays, magnetic resonance imaging (MRI), ultrasound scanning, and computed tomography (CT) scanning produce pictures of the inside of your body without surgery to give your doctor important information about your overall health. If your doctor has ordered one of these tests for you and you don't understand what exactly is going to happen, ask questions so you can feel more comfortable about having the procedure. Diagnostic techniques are changing rapidly, and newer techniques will undoubtedly be available in the near future.

Blood Test

A sample of your blood can provide many clues about the quantity and quality of the individual blood cells and whether your blood can clot normally. To obtain a sample of your blood, a medical technician will draw blood with a needle and syringe from your forearm and send it to a laboratory. At the laboratory, your blood will be analyzed in several ways. Tests will be done to check the number of your red blood cells and the concentration of hemoglobin inside them. Hemoglobin is the substance in red blood cells that carries oxygen throughout the body. A low red blood cell count or too little hemoglobin indicates anemia. Blood tests also will be conducted to detect the number of white blood cells, which have a major part in defending the body against infection. If an infection is present, the number of white blood cells in your blood will rise. The appearance of your blood cells is also important. Abnormally shaped red or white blood cells can signal the presence of diverse conditions such as sickle-cell disease, leukemia, or mononucleosis. Finally, your blood will be checked to see how well it clots by examining the number of blood cells called platelets, which help stop bleeding.


Cholesterol Levels Elevated levels of the fats known as cholesterol in your 89

blood increase your risk for heart disease. When the excess fats build up inside Preventive the walls of your arteries, they narrow the arteries, obstructing blood flow to your heart. When the heart receives less blood, it gets less oxygen, which is transported by red blood cells. Your heart sends out warning signals in the form of pain and discomfort known as angina. When the blockage in the arteries supplying blood to your heart causes severe obstruction, resulting in a heart attack (see page 207), the heart muscle can become permanently damaged.

Cholesterol comes in two forms: low-density lipoprotein (LDL), the "bad" cholesterol, and high-density lipoprotein (HDL), the "good" cholesterol. Somewhat like a delivery truck, LDL cholesterol carries most of the fat in your blood and deposits the excess inside your artery walls. Like a garbage truck, HDL cholesterol removes fat from your blood, preventing it from building up in your arteries. When testing your cholesterol levels, your doctor measures your total blood cholesterol as well as your LDL and HDL levels by taking a sample of your blood and having it analyzed in a laboratory.

A desirable total blood cholesterol level falls under 200 milligrams per deciliter of blood. Doctors consider cholesterol levels above 200 to be high. One in five Americans has a total cholesterol level of 240 or greater, placing that person at risk of a heart attack. Your LDL cholesterol levels should be under 100, and HDL levels should be 40 or higher. The higher your HDL level, the lower your risk for heart disease.

All men over 20 years of age should have their total cholesterol levels checked at least once every 5 years. Your level of LDL cholesterol also should be tested if your HDL is less than 40 or if your total cholesterol is 240 or higher—200 if you have two or more risk factors for heart disease. Talk to your doctor about your personal risk factors for heart disease. Don't hesitate to ask him or her anything you do not understand about cholesterol testing.


Your urine provides crucial information about the presence of any disorders of the kidneys or bladder. If your doctor orders a urinalysis, you will be asked to pass some urine and collect a midstream sample (urinate for several seconds before collecting the sample of urine) in a small container, either at home or in the doctor's office. If you are uncircumcised, you should pull back your foreskin and wash the tip of your penis with soap and water before urinating to ensure that your urine remains sterile. Your urine may be tested in a laboratory or in the doctor's office, using special strips that the doctor can dip into the urine to test for any abnormalities. The presence of particular substances such as blood or sugar in the urine can indicate certain diseases. For example, the presence of protein in the urine can signal some types of kidney disease.

90 X ray

Staying Healthy

The most common scanning test is the X ray, in which electromagnetic radiation passes through a body part to produce a picture of internal structures on film. X rays are a good way of showing dense areas of the body, such as bones or a tumor, that allow only a few rays to pass through. These dense areas show up as white areas on the film. Doctors use X rays to examine the chest, skull, and spine and to view a bone that may have been fractured. Even organs filled with fluid, gas, or air—such as the arteries, colon, or bladder—can be viewed with X rays if the organs are first enhanced with a special liquid dye called a contrast medium. The contrast medium is injected, swallowed, or inserted through the anus; then the doctor or technician takes a series of X rays as the contrast medium moves through the organ to facilitate viewing. Getting an X ray is safe because today's X-ray equipment minimizes your exposure to radiation.

Lower Your Cholesterol In Just 33 Days

Lower Your Cholesterol In Just 33 Days

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