More medical tests every man should have

5. Vitamin D test

Recently, doctors have realized that vitamin D is a key nutrient that helps maintain strong bones and protect against cancer, infection, and other health conditions. For example, a study last year found that men with low levels of vitamin D had a higher incidence of heart attack. Most men have no idea if they're D-deficient or not, though a simple blood test can tell. If you live in a northern climate, work indoors, or don't drink a lot of milk, chances are your vitamin D level is low. If so, your doctor will recommend taking a vitamin D supplement.

What it is: A blood test, often done along with the cholesterol and lipid panel, to check the level of vitamin D in your blood. You want your reading to be between 30 and 80 nanograms per milliliter, though some experts argue that 50 nanograms should be the lowest level considered normal. Many experts recommend the 25(OH)D3 test as providing the more accurate measurement.

When to start: Age 40; sooner if you have signs or risk factors for osteoporosis. As we age, our bodies become less efficient at synthesizing vitamin D from the sun, so after the age of 40 it's more likely that you'll become D-deficient. Also, if you have any signs of low bone density, such as a fracture, your doctor will want to test your vitamin D along with your bone density.

How often: Although vitamin D testing isn't yet required or listed on the official schedule of recommended tests, more and more doctors are recommending it as an annual test after age 45.

6. Colonoscopy or sigmoidoscopy

Colorectal cancer, which is cancer of the lower part of the intestines, is curable in 90 percent of all cases -- as long as it's caught early. And screening tests that look inside the colon, called colonoscopy and flexible sigmoidoscopy, are the secret to catching it early.

Unfortunately, this still isn't happening as often as it should. Currently, 39 percent of cases are already stage III or IV when discovered. This test is considered so lifesaving that news anchor Katie Couric allowed hers to be presented on live TV as an educational campaign to raise awareness after her husband died of colorectal cancer. Colorectal cancer is the third leading cause of death from cancer for men, after lung and prostate cancer, so it's important to take it seriously.

What it is: An examination of your colon using a tiny scope and camera, which are inserted through the rectum. A colonoscopy can see the whole colon, while a sigmoidoscopy can see only the sigmoid, or lower section of the colon.

When to start: Age 50 for those with no risk factors. If, however, you have a first-degree family member who's had colon cancer before the age of 50, begin colonoscopy screening when you're ten years younger than the age at which your family member was diagnosed. If a family member was diagnosed at 45, for example, you should have your first screening at 35.

How often: Flexible sigmoidoscopies should be repeated every five years, and a colonoscopy should be repeated every ten years. A computerized imaging technique called virtual colonoscopy is gaining popularity at some medical centers, but many doctors still consider it experimental and some insurers, including Medicare, don't cover it.

7. Fecal occult blood test (FOBT)

Although it sounds otherworldly, the word occult simply refers to the fact that this test checks for blood in the stool that's not visible to the eye. This is the least invasive screening tool available. A chemical solution is used to test a stool sample for the presence of blood, which can indicate intestinal conditions such as Crohn's disease and ulcerative colitis, or colorectal cancer.

Colorectal cancer still strikes more men than women -- more than 50,000 men are diagnosed with the disease every year.

What it is: A stool sample test that looks for blood in the stool using a chemically treated pad that turns blue in the presence of blood. Three stool samples are collected on consecutive days, since cancer and other conditions may not bleed consistently.

When to start: At age 50; your doctor may suggest it earlier if there's cause for concern about intestinal conditions.

How often: Yearly after age 50