Brain & nervous system lab tests

Can show how much vitamin D your body has in reserve. Your skin makes vitamin D from sunlight, and you also get it from some foods.

Vitamin B12 helps your body make red blood cells and keeps your nerves and brain working well. This shows how much B12 is in your blood.

Shows the folate, a B vitamin, stored inside your red blood cells. Because red cells live for a few months, it can reflect your longer-term folate, not just recent meals.

Measures folate, a B vitamin, in the liquid part of your blood. It can mostly reflect what you’ve eaten over the last few days.

Magnesium is a mineral that helps your muscles, nerves and heartbeat work and keeps your bones strong. Most of it sits in your bones and cells, so a blood level can show only part of the picture.

Rather than the fluid part of your blood, this measures magnesium inside your red blood cells. Some doctors use it to get a fuller sense of your body’s magnesium stores.

Homocysteine is a substance your body makes as it breaks down protein. It can build up when you’re low in certain B vitamins or when your kidneys aren’t clearing it well.

Chromium is a mineral found in tiny amounts in food, and it may help insulin manage your blood sugar. A blood test is mostly used to check for too much exposure.

Cobalt is a metal your body uses only as part of vitamin B12. Higher blood levels may point to extra exposure, such as wear from a metal hip implant or work with metals.

Coenzyme Q10, or CoQ10, is a substance your cells use to make energy. Your body makes its own, and levels can fall with age.

Your body needs small amounts of copper, a mineral, to make red blood cells, use iron and keep nerves healthy. This looks at how much copper is in your blood.

Looks at the copper inside your red blood cells, rather than the copper in the liquid part of your blood. Copper helps your body make red blood cells, use iron and keep nerves healthy.

Your thyroid, the gland in your neck that helps set your energy and metabolism, needs iodine to make its hormones. A blood level can mostly reflect how much iodine you’ve had recently.

Manganese is a trace mineral your body needs in small amounts for bones and for turning food into energy. Most people get plenty from foods like whole grains, nuts, beans and tea.

Methylmalonic acid is a substance that can build up when your body is short on vitamin B12. It can catch a B12 shortage that a B12 test alone may miss.

Selenium is a trace mineral that your thyroid, the gland in your neck that helps set your energy level, needs to work well. It also helps protect your cells from damage.

Checks your vitamin A level. Vitamin A helps you see in dim light, keeps your skin healthy and supports your immune system.

Shows your level of thiamine, also called vitamin B1. Thiamine helps your body turn food into energy and keeps your nerves and heart working well.

Looks at riboflavin, also called vitamin B2. It helps your body turn food into energy and keeps your skin and eyes healthy.

Checks your pantothenic acid, also called vitamin B5. It helps your body turn food into energy and make fats.

Measures vitamin B6, which your body uses to make brain chemicals that affect mood, build red blood cells and support your immune system.

Measures vitamin C, which your body uses to make collagen, the protein that keeps skin and blood vessels strong. It also helps wounds heal and helps you absorb iron from plant foods.

Zinc is a mineral that helps your immune system fight germs, helps wounds heal and supports your senses of taste and smell. This shows how much zinc is in your blood.

Looks at zinc inside your red blood cells, rather than in the liquid part of your blood. Because red cells live for months, it may give a longer-term picture.

Measures folate, a B vitamin your body uses to make red blood cells and help new cells grow. It’s one part of a broader nutrient check.

Measures the iron moving through your blood right now. It can change through the day and after meals, so it’s read together with tests of your iron stores.

Cortisol is your main stress hormone, and it helps control blood sugar, blood pressure, and energy. It can peak in the morning, which is why it’s checked then.

A hormone your adrenal glands, small glands on top of your kidneys, make on the way to cortisol, your main stress hormone. A buildup can mean one step in that process isn’t working as it should.

Your adrenal glands, which sit on top of your kidneys, pass this hormone along as they make other hormones. A buildup can point to a hold-up at one step in that chain.

A hormone your adrenal glands and ovaries make on the way to other hormones, including cortisol. High levels can be a sign of an inherited condition that can cause extra androgens, hormones like testosterone.

ACTH is a signal from your pituitary, a pea-sized gland at the base of your brain, that tells your adrenal glands to make cortisol. It’s usually read alongside a cortisol result.

Aldosterone is a hormone from your adrenal glands that tells your kidneys how much salt and water to keep. It helps control your blood pressure and your potassium level.

Measures cortisol, your main stress hormone, with a very precise lab method called mass spectrometry. It’s less likely than standard tests to be thrown off by similar hormones or some medicines.

Pregnenolone is the starting material your body uses to make other steroid hormones, including estrogen, progesterone, testosterone, and cortisol. It’s made mainly in the adrenal glands and ovaries.