Testing for Nutrient Deficiences

Do you suspect that your symptoms are caused by a vitamin or mineral deficiency? You may be right. But how do you tell?

Diagnosing a micronutrient deficiency is not always easy. Our biochemistry is very complex, symptoms can be misleading, and lab testing doesn't always show the whole picture.

As a doctor, I use all available information to assess the likelihood of nutrient deficiencies. I look at all the symptoms, I evaluate diet and and digestive function, I look at lab tests and genetics and I put it all together to identify deficiencies.

Blood Testing for Nutrient Deficiencies

You would think that diagnosing a nutrient deficiency would be as simple as taking a blood test, but that is not the case. Most doctors order serum vitamin tests. This means that they evaluate the level of a specific vitamin in your bloodstream. But this has many limitations. First, it can only evaluate vitamins that are water soluble. Fat soluble vitamins, like vitamin A, D, E, and K, cannot be evaluate this way. Second, it only tells you how much of the vitamin you are getting in your diet or supplements. It does not tell you how well your body is using those vitamins and if they are actually getting to where they need to be (inside your cells). This is why I don't use serum vitamin tests.

The best blood test that I have found to date is Spectracell's micronutrient test. In this test, they take your white blood cells from your blood to assess nutrient levels inside the cell. I have found this to be a much more accurate way of assessing nutrient levels. But I have found that it doesn't always explain the whole picture (perhaps because it is only looking at one type of cell in the body). 

Other Testing for Nutrient Deficiencies

There are other types of testing that can provide us with direct or indirect information about nutrient deficiencies.

An organic acids test (urine test) can provide a lot of information about how your biochemistry is working and thus indirectly reveal deficiencies. 

Looking at metabolite levels in biochemical pathways can provide indirect information about nutrient deficiencies. These are typically blood or urine tests.

Genetic testing (particularly in the methylation pathways like MTHFR) can reveal how our body utilizes nutrients and what we call functional deficiencies.

Using these types of tests often does not provide direct answers, so I recommend using the information from these tests to confirm what the direct tests or your symptoms are telling you.

Symptoms of Nutrient Deficiencies

Symptoms are also an important part in determining nutrient deficiencies. I often see that serum blood tests do not reveal deficiencies and yet the symptoms do. And when we treat based on the symptoms, they resolve. We need to remember that we are all different when it comes to our biochemistry. This means we may have unique nutrient needs and the reference range from a lab test does not always apply to us. So listen to your body. Often, it is safe to just do a trial and error. If you think you have a deficiency based on your symptoms, you can try supplementing to see if your symptoms improve. I do recommend always checking with a doctor before starting a supplement because not all supplements are safe for every person.

Check out the infographic below for common symptoms of nutrient deficiencies.

Vitamin Deficiency Infographic


I'm Dr. Carly and my mission is to create a health revolution. I believe that another prescription is not the answer. I believe in using natural therapies that go beyond the symptoms. And I believe that doctors should spend way more than 7 minutes with a patient.