Blood Tests You Need (and Don't)

Some of these may be part of routine physicals, though not all experts agree on how often they should be given. Others are done only once or occasionally. They’re typically covered by insurance, but it’s wise to check first.

By measuring 14 different substances, this provides information about your liver and kidney health, and bone strength. It also checks your glucose levels to determine your risk of developing diabetes, and evaluates the state of your electrolytes and bodily fluids, which help regulate blood pressure and heart rhythm.

If you have a chronic condition such as high blood pressure or you take at least one medication regularly, your doctor will want to run this test annually to make sure that your meds aren’t harming your liver or kidneys, says Michael Hochman, MD, MPH, an internal medicine physician in Los Angeles. The independent U.S. Preventive Services Task Force (USPSTF) recommends that healthy adults between 35 and 70 have their glucose levels checked every three years.

This test, one of the most common, measures red and white blood cells and platelets to help identify issues such as infections and anemia. The CBC is an important diagnostic tool, but the USPSTF doesn’t include the test on its list of recommended routine screenings.

Typically, this checks your total cholesterol: HDL ("good") cholesterol, LDL ("bad") cholesterol, and fatty substances called triglycerides. High or borderline high LDL results indicate an increased risk of heart disease, as do too-low levels of HDL. The American Heart Association (AHA) and the American College of Cardiology (ACC) recommend that those 19 and older have this test at least every five years. (If you have heart disease risk factors, your doctor may want to check your lipids more often.)

A high level of Lp(a), a cholesterol-carrying substance in your blood, is associated with a higher long-term risk of a heart attack or stroke. "It can help us decide if we need to start you on a statin drug," says Nieca Goldberg, MD, a cardiologist at NYU Langone Health in New York City. All adults should have this one-time blood test at some point, ideally before age 40, according to the AHA and ACC, she says.

An A1C test measures your average blood sugar levels over the past two to three months. "Fasting blood tests to measure glucose levels are just snapshots of a single point in time," says Brintha Vasagar, MD, chief medical officer of Progressive Community Health Center in Milwaukee and a spokesperson for the American Academy of Family Physicians. "An A1C test gives us a more complete picture." The Centers for Disease Control and Prevention recommends that everyone 45 and older have a baseline test, and that some, like those at higher risk for prediabetes and diabetes, do this earlier.

An abnormal result on this test for thyroid disease may suggest an overactive or underactive thyroid (hyperthyroidism or hypothyroidism). There’s no consensus on routine screening. The USPSTF says there’s not enough evidence for or against it. The American Association of Clinical Endocrinologists says "older patients" should have the test, and the American Thyroid Association recommends it every five years if you’re over 35. If you have thyroid disease symptoms, your doctor may run tests such as the T4, too.

In its 2024 guidelines, the Endocrine Society advised against routine screening for healthy adults. But it’s appropriate for those at higher risk for deficiency, which includes people with osteoporosis or a condition that interferes with vitamin D absorption, like inflammatory bowel disease, Gold says.

Groups like the AHA recommend this test—which measures levels of a protein that attaches to fat particles in blood—if you have type 2 diabetes, high triglycerides, or cardiovascular disease. It’s then done each time you get a lipid panel.

Some tests measure reproductive hormones in women, like follicle-stimulating hormone, luteinizing hormone, and estradiol. Cory Fisher, DO, a family medicine physician at Cleveland Clinic, sometimes orders them if he thinks a woman may be going through premature menopause. As for testosterone tests for men, "we only do this if they have symptoms like erectile dysfunction and a dramatic decrease in their sex drive," he says.

Have allergy symptoms? Tests for allergen-specific antibodies may help identify the substances causing you problems. But because these have a high false-positive rate, your doctor should also run other tests—like an oral food challenge—for confirmation, Gold says.

Autoimmune diseases such as rheumatoid arthritis can be hard to diagnose. Blood tests such as those for C-reactive protein or erythrocyte sedimentation rate (how long it takes red blood cells to fall to the bottom of a test tube) can screen for inflammation, which may indicate an autoimmune condition, Hochman says. Other tests may provide more information. For instance, an antinuclear antibody test can help diagnose lupus.

Gut health, hormone levels, heart disease, even your biological age: There are tests available for just about any health condition you’re curious about. Some come in kits that include multiple tests. You can order them online (prick your finger with a lancet at home and send your sample off for analysis) or simply walk into certain labs to get those you want.

The appeal is easy to understand: DTC blood tests may offer privacy—if you want that—and an alternative to the hassle of time-consuming medical appointments.

But you’ll want to be aware of potential pitfalls. For instance, learning that you’re at higher risk for a certain condition doesn’t necessarily mean you’ll develop it, or that there are preventive steps to take. "There are reasons we don’t screen for all of these biomarkers in everybody. Many are for diseases that are extraordinarily rare," says Sheldon Campbell, MD, PhD, associate director of clinical microbiology for Yale-New Haven Health in Connecticut, and chair of the Point of Care Testing Committee for the College of American Pathologists.

And DTC tests aren’t tightly regulated, contrary to what more than 50 percent of respondents in a 2022 University of Michigan poll thought. Some are approved by the Food and Drug Administration, meaning the agency has reviewed the manufacturer’s data and concluded that it’s reliable. But this doesn’t mean the results are useful.

If you’re going to use a home test, stick with those that are FDA-approved. (To find them, go to fda.gov, search for "approved home and lab tests," and enter the test you’re interested in.) For tests that aren’t FDA-approved, check the manufacturer’s website to make sure it uses a laboratory accredited by the Clinical Laboratory Improvement Amendments or the College of American Pathologists.

And always share the results you receive with your doctor. "Your physicians can help you interpret what these results mean and figure out what you need to do moving forward to keep you healthy," says Jeffrey Kullgren, MD, an associate professor at the University of Michigan in Ann Arbor.

Better yet, talk with your doctor first. "These tests are expensive and not covered by insurance," Kullgren says, "so you really want to make sure that you need them, and check if they can be ordered by your doctor to save you money." Here’s a rundown of five of the most popular types.

Some labs offer a food allergy panel, which measures immunoglobulin E (IgE) antibodies in your blood. These are substances your body may produce in response to allergens such as peanuts, some tree nuts, fish, shrimp, sesame seeds, cow’s milk, egg whites, and wheat. Others sell tests marketed for food sensitivities or intolerances, which some say can cause symptoms like gastrointestinal trouble. DTC food allergy tests range from $140 to $359, and food sensitivity tests from $140 to $300.

You’re best off doing food allergy tests in a doctor’s office, according to Gold, where they’re more likely to be covered by insurance. "You’ll have to work with your doctor anyway if anything in the test comes back positive," he says.

There’s likely no reason to do food sensitivity testing, which measures IgG, a different antibody than allergy tests check, Gold says. High IgG levels often mean only that you eat a suspect food regularly, he says—not that you’re sensitive to it.

At-home blood tests are available for STDs such as genital herpes, hepatitis A and B, HIV, and syphilis. "There are some advantages to these tests—mainly that you’re doing them in the privacy of your own home, if you are nervous going to a clinic or asking your doctor to run them," Hochman says. But you’ll likely still need to contact your doctor if you get a positive result. And the tests can be costly. A five-panel STD test for hepatitis, chlamydia, gonorrhea, syphilis, and trichomoniasis costs about $170 out of pocket.

For women, these may be expansions of what a doctor might order to determine whether they’re in perimenopause. In addition to measuring reproductive hormones such as follicle-stimulating hormone, luteinizing hormone, estradiol (estrogen), and progesterone, they may also check testosterone, DHEA-S, and various thyroid hormones. For men, a test package might look at testosterone, sex-hormone-binding globulin, albumin, estradiol, and prolactin. These packages can cost $150 to $300.

Skip them, say the experts we interviewed. For women, hormone levels change rapidly in middle age, and a test at a single point in time won’t likely be definitive. As for thyroid hormone levels, "you can get the exact same tests done at your doctor’s office, and they’re usually covered by insurance," Campbell says. The same is true for testosterone testing for men.

These may measure everything from cholesterol to A1C levels to markers of inflammation like C-reactive protein, and can range from around $50 for a basic lipid panel to close to $200 for a more extensive kit. Many are the same screenings your doctor would have you do routinely, according to Goldberg. "You can ask your doctor to order a lipid panel and an A1C [which measures blood sugar control], and usually, you don’t have to pay anything because it’s covered by insurance under preventive care," she says.

Some DTC heart health kits contain additional tests as well, such as one for what’s called high-sensitivity C-reactive protein (hsCRP). This test, which checks for an inflammation marker, may be helpful for some people at higher risk of heart disease. Your doctor can also perform it, so you may want to ask whether it’s right for you.

These multitest kits, which range from about $300 to almost $900, may check more than 80 biomarkers and provide a personalized health score. They often include standard lab tests, such as a complete blood count, comprehensive metabolic and lipid panels, and a check of your A1C, insulin, vitamin, and hormone levels and thyroid function, as well as hormone tests. Some also test for substances like nicotinamide adenine dinucleotide (NAD) to help gauge your overall biological age.

But it’s not clear just how helpful the results are. "They throw a whole bunch of biomarker results on you, the consumer, who doesn’t have any idea of what to make of them," Campbell says. He likens it to watching a YouTube video in order to learn how to fix his car’s brakes.

If you’re curious about these products, Campbell recommends talking to your primary care provider first. Your doctor may already order some of the tests for you during routine screenings or can if you request it.

Alzheimer’s disease has long been difficult to diagnose in its early stages. But blood tests that measure levels of key proteins in amyloid brain plaques—which may indicate the onset of the disease—have become available in the past few years.

Tests such as Lumipulse and Elecsys pTau181 are designed to help pick up more cases sooner so that people can take advantage of treatments that may slow the progression during the condition’s initial stages, says Jeffrey Kullgren, MD, an associate professor at the University of Michigan in Ann Arbor. But neither test is diagnostic on its own, and Lumipulse can have a false-positive rate of up to 40 percent, according to a 2026 JAMA Neurology research letter. This means it may indicate a problem where none exists.

Still, it’s reasonable to ask about these tests if you have concerns about yourself or a loved one. If the result is positive, your doctor should follow up with a cognitive assessment and imaging tests, such as an MRI.