5 Blood Tests That Are Worth the Prick

The Test That Can Help You Avoid a Heart Attack

What it does: A CRP test identifies the presence of C-reactive proteins, which are indicators of inflammation in the body.

Why this matters: Chronic inflammation can do serious damage to healthy tissue, eventually leading to blood clots and accelerate the buildup of plaque in the arteries. According to the American Heart Association, people with high C-reactive proteins are twice as likely to suffer cardiac arrest as those with low levels.

Who should get it: This test makes the most sense for those who are over age 40 and have slightly high cholesterol, a large waistline, a family history of heart disease or are a little overweight. All of these factors could mean that you're at "intermediate" risk for a heart attack or stroke and can help your doctor decide if you should start a statin drug, says Janet Pregler, MD, the director of the Iris Cantor-UCLA Women’s Health Center. (Statins, which are widely prescribed, usually involve a lifelong commitment and can have significant side effects, like muscle pain, cataracts, liver damage, and an increased risk of diabetes, especially in post-menopausal women.)

What else you should know: This is not a standard test for women, and most insurance plans don't cover it, Pregler says.

The Blood Test That Could Discover Why You're Not Feeling Quite Right

What it does: A vitamin B12 level test measures the amount of vitamin B12 in your blood.

Why this matters: A deficiency in this vitamin has been linked to anemia, nerve issues, memory problems (and dementia), crushing fatigue, mood disorders—many of the vexing ailments that can seriously disrupt a woman's life, says Sandra Adamson Fryhofer, MD, an adjunct clinical associate professor at Emory University.

Who should get it: Vegans and vegetarians are more likely to be deficient in B12 because they don't consume animal products, which are among the best sources of this vitamin. People who have low stomach acid—whether due to age or medication for acid reflux—are also at risk, because the acid helps absorb the vitamin, says Fryhofer. She checks her patients as part of their wellness visits, but if your doctor doesn't, get your B12 and your D levels assessed if you're just "not feeling right."

What else you should know: More vitamins aren't always better, Fryhofer says. An excess of vitamin B12 can overload your kidneys, and too much vitamin D can increase your risk of kidney stones.

An Essential Blood Test for Women

What it does: A thyroid-stimulating hormone (TSH) blood test can check for thyroid gland problems. A higher-than-normal level of TSH could mean your thyroid is underactive (hypothyroidism), while a lower-than-normal level could mean it's overactive (hyperthyroidism).

Why this matters: The thyroid affects everything women really care about, says Fryhofer, including weight, menstrual periods, hair, skin, muscles, energy levels and mood.

Who should get it: Women who just had a baby or are over 60 are more likely to have an underactive thyroid, but many doctors routinely do TSH tests on patients to make sure the gland is working properly (ask your doctor to be sure).

What else you should know: Untreated for long periods of time, hypothyroidism can bring on a myxedema coma, a rare but potentially fatal condition. But thyroid issues are usually straightforward and can be addressed with prescription supplements, says Fryhofer, so it's never a bad idea to get this test.