When It’s Worth It to Optimize Health

Micronutrient testing, or nutrition blood tests, are often very insightful for helping people improve their health. 

But there are some important details you should know about these tests before you pursue them. 

Micronutrient testing overview

Best micronutrient test types

Some blood tests are very accurate when you get them tested, such as vitamin D levels or iron levels.  

However, not all blood tests are what meets the eye.

For example, nutrient tests like vitamin B12 levels can be helpful, but normal ranges don’t usually list optimal levels. 

In order to get the best micronutrient tests, you will need to have some savvy about what types of tests to order or have your healthcare provider order.   

This is because most vitamins and minerals aren’t stored in the blood.  And sometimes urine markers or organic acid tests are more helpful than blood tests.

Best types of vitamin tests

Micronutrient levels of vitamins can make or break your health.  

But, checking blood levels can be tricky because most vitamins aren’t stored in the blood. 

Rather, they tend to be stored in muscle, fat, liver, and other tissues in the body. 

Still, overall health depends on getting optimal nutrients from the diet and sometimes supplements. 

The only way to know if you are getting enough of some types of nutrients is by testing blood or urine levels of these nutrients. 

Here is a breakdown of tests that are accurate and those that aren’t as accurate. 

Vitamins tests that are always worth testing

• Vitamin D– the test for vitamin D is called serum 25-hydroxyvitamin D. It is a very accurate marker of vitamin D deficiency. Optimal levels are over 40 ng/ml [R]. Vitamin D deficiency is a risk factor for many diseases so you should ideally check your blood levels twice a year. It is critical for your immune system, brain health, joint health, muscle health, and more. 
• Homocysteine-high levels of homocysteine usually indicate deficiencies of folate better than folate tests [R].  It also is elevated if you are low in vitamin B6 or vitamin B12 [R, R].  
• Vitamin B12-plasma vitamin B12 and urinary methylmalonic acid are good tests to check if you suspect vitamin B12 deficiency. Of note, methylmalonic acid levels are high with vitamin B12 deficiency. .  Optimal plasma vitamin B12 blood levels are over 400 ng/ml so reference ranges on tests underestimate deficiency [R].  Your body needs plenty of vitamin B12 for energy and to help protect nerves. Luckily, supplements of vitamin B12 have no toxicity levels. 

Possibly worth testing

• Vitamin A-serum levels of vitamin A are low if intake is low. However, it only is accurate with severe deficiency. 
• Vitamin B1 (thiamin)- a test called erythrocyte transketolase index or urine levels of branched-chain keto acids are markers of thiamine nutritional status. Taking a natural stress B-complex vitamin is much cheaper than going to the expense of checking vitamin B1 levels. 
• Vitamin B2 (riboflavin) is tested by checking urine ethylmalonate.  This test measures your riboflavin levels indirectly.  High levels indicate deficiency. Adding a natural B-vitamin to your routine is much cheaper than getting this test and supplementing is safe. 
• Vitamin B6– is tested by checking erythrocyte transaminase (EGPT) in the blood.  These levels are low with vitamin B6 deficiency.  Homocysteine can be checked instead-this level will be high with vitamin B6 deficiency. Certain medications commonly cause vitamin B6 deficiency, such as birth control and blood pressure pills. P5P is the preferred type of B6 supplement.
• Folate-requires a special micronutrient test via gene testing.  It is called MTHFR gene testing because over 40% of people don’t metabolize folic acid [R].  You can also check plasma homocysteine and when it is high, you may be low in folate. You can also check red blood cell folate levels.  Supplements of natural folate are cheap, so it may be better to just take a good multivitamin with natural folate than get expensive tests.  
• Vitamin E-deficiency of vitamin E can be tested by measuring tocopherol/triglyceride ratios in your serum. A much larger percentage of the population has vitamin E deficiency than previously thought. Make sure to supplement natural vitamin E if you are adding supplements.

Not worth it

• Vitamin C-has such a short lifespan in the body so measurements of vitamin C aren’t typically accurate. 
• Biotin-lab tests are currently available in research but not available to the public. 
• Vitamin K-lab tests aren’t readily available except in research at this time. Supplemental vitamin K2 is a smart option for most people instead.
• Vitamin B3 (Niacin)-tests are difficult to interpret and moderate supplementation is safe. 

Mineral tests

A micronutrient test you also may want to consider is for certain minerals. Similar to vitamin tests, some mineral tests are accurate and some are not.  

In other words, getting a blood test for mineral deficiency can be as problematic as checking vitamins. 

Let’s take a look. 

Minerals possibly worth testing

A blood test for minerals can be useful in some situations.  The following minerals can be tested.  Keep in mind that they can be very expensive to test. 

Magnesium-you can measure magnesium by a blood test, but make sure to have your doctor check RBC magnesium instead of serum magnesium [R]. Even if your blood levels are normal for magnesium, clinical signs of magnesium deficiency may mean you still need to supplement magnesium.

Selenium-RBC selenium levels can be an indicator of your selenium status [R]. You can also test the enzyme called glutathione peroxidase as a functional marker of selenium deficiency.

Chromium– it isn’t possible to get accurate blood levels, but an indicator of chromium status is checking for an abnormal glucose-insulin tolerance test.  It normalizes when you give chromium if you are chromium deficient. 

Copper– tests for nutrient levels of copper are red blood cell copper, ceruloplasmin, and urine copper levels.  Excess copper levels are just as common as deficiency due to the use of copper pipes or cookware which can lead to poisoning. 

Iodine-iodine deficiency is relatively common and you can test urinary iodine levels along with TSH, T3, and T4 levels to determine iodine status [R].  Alternatively, you can help assure you are getting enough iodine by getting a high-quality multivitamin with minerals. 

Iron-deficiency of iron is very common, so you should have your doctor check ferritin, transferrin saturation, and total iron-binding capacity to determine your levels [R].  Contrary to popular thinking, hemoglobin levels aren’t adequate when screening for iron deficiency. Around half of women with iron deficiency have normal hemoglobin levels.

Not very accurate

Zinc-getting a zinc test is difficult because blood levels account for only 0.5% of total zinc. Urine zinc tests aren’t very accurate either. When in doubt, getting a broad spectrum multivitamin with minerals will help assure that your body gets enough zinc.  Many medications also rob the body of zinc and restrictive diets can cause a zinc deficiency.  So, it’s really important for many people to supplement a multivitamin with minerals that contain zinc.  Supplemental zinc may even help prevent diseases like diabetes [R]. 

Calcium-blood levels don’t usually reflect dietary intake very well.  Urine calcium is a better marker of calcium status, but it can also point to other issues such as kidney disease, kidney stones, and parathyroid issues [R].

Sodium-can tell more about hydration status than it does about sodium status. There really isn’t a great nutrient deficiency test for sodium. However, a good practitioner can interpret serum sodium when taking into account your other health factors. 

Other nutrient tests

Macronutrients like fats are also challenging to test. 

But getting your blood fatty acids tested can be really helpful too. 

For example, checking your omega 6 fatty acid-to-omega 3 fatty acid ratios can tell you a lot about your risk for heart disease. 

Grassroots Health has a kit that tests both your omega 3 index and vitamin D levels. Plus, the company is very helpful for interpreting your result. The result is given as a percent of total RBC fatty acids. This is a long-term and stable marker of omega-3 status throughout the blood and tissues.Best micronutrient testing options

A functional medicine doctor or functional nutrition dietitian is usually trained in nutrient analysis.  So it is best to visit a local provider where they can determine the best micronutrient testing options for you.  

They can do a more thorough clinical assessment to help you narrow down what you should check. 

Micronutrient testing at home

One source of micronutrient testing can be a micronutrient test kit that you order online.  From there, you can take it to your local lab where they can draw your blood for you.

Then you send in your blood sample and the lab testing company sends you your results. A Spectracell micronutrient test or Let’s Get Checked are examples of reliable micronutrient blood test kits for home. 

Micronutrient testing cost varies a lot by the type of tests you order and the company you go with. 

And these tests can still have their own set of limitations because they often don’t measure both vitamin B12 and methylmalonic acid as an example. 

Importance of Micronutrients

In each split second, your body’s micronutrients are helping the body function.  They are critical for absolutely every cell in your body.  

This is why testing for levels seems like such a smart idea.  And it sometimes is as in the case of the vitamins and minerals listed above that are worth testing.

Eating a great diet full of whole foods is the cornerstone of getting enough nutrients as well. 

As mentioned previously, adding a natural vitamin and mineral supplement can go a long way to fill in micronutrient gaps in the diet. 

A healthy diet isn’t often enough.  Soil concentrations of nutrients have slowly gone down since the advent of industrial farming [R].   

And let’s face it; Americans love to eat low-quality, highly processed foods that have minimal nutrients.  

I’ve personally never met a human that met all of their nutrients for optimal health with their diet alone. And I’ve worked as a dietitian for over 20 years, so that’s a lot of people I’ve met along the way. 

When comprehensive micronutrient testing is worth it

Some people have digestive issues that cause nutrients to be robbed from the body.  Examples are digestive disorders like celiac disease, Crohn’s disease, small intestinal bacterial overgrowth (SIBO), and short gut syndrome. 

Additionally, surgeries that remove part of the digestive tract can majorly reduce the body’s ability to absorb nutrients. 

If you have any of these conditions, it makes sense to have a more thorough nutrient panel for both blood and urine tests as described above. 

Interpreting micronutrient testing levels

It is important to know that “normal” reference ranges for lab values do not always mean optimal vitamin levels. 

Good examples of this are vitamin D.  The normal range is anything over 20 ng/ml, but extensive research shows that optimal vitamin D levels are usually over 40 ng/ml. 

Another perfect example is vitamin B12.  Reference ranges can show that normal levels are anything over 200 pg/ml. But people can be deficient and get nerve damage with anything under 400 ng/ml of vitamin B12. 

And keep in mind, the type of test that is ordered is just as important.  Serum tests are commonly ordered.

But red blood cell tests are sometimes more accurate than serum levels. This is the case for magnesium and selenium. 

Micronutrient testing summary

Specific nutrients like vitamin D, iron, and vitamin B12 are easy to test and can be checked just about anywhere. 

However, if you are looking for more advanced nutrient testing like selenium, vitamin E, vitamin A, and other B-vitamins, you are going to need to seek out specialized and expensive blood and urine tests.

Rather, it makes sense to get a comprehensive natural multivitamin with minerals instead in most cases. The exception to this rule is usually in people who have malabsorption or major digestive issues. In these cases, nutrients don’t absorb well.