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What is Functional Lab Testing?

Functional lab testing helps evaluate how your body is functioning on a range of information relating to your body’s ecosystem instead of diagnosing a specific disease. The results of functional labs can help immensely in finding the root cause(s) of challenges to your health such as hormonal imbalances, gut problems, skin concerns, etc. Testing may include blood, stool, urine, saliva, or hair samples to give insight into a variety of systems including:

  • Metabolic
  • Nutritional
  • Endocrine
  • Gastrointestinal
  • Hormonal
  • Immune
  • Genetic
  • Detoxification
  • Others

Standard (Normal) Lab Results vs. Optimal Lab Results— A Functional Medicine Perspective

The primary objective of deep-diving into functional lab testing results is to look for any disruptions within your body- finding any deviation from optimal results and adjusting them. Your body is complex and there may be different root causes that may show up as symptoms. For interpreting results, most standard lab reference ranges are very wide allowing disease progression to possibly go undetected. Functional medicine optimal ranges are usually much narrower, allowing practitioners to foresee possible dysfunction so they may intervene early with nutrition, supplements, and lifestyle adjustments to help patients prevent disease. Most functional medicine practitioners have their own preferences, narrowing the range by 25% off of the significant numbers in the standard range. However, over time, I’m hoping more of a consensus is reached and a gold standard of care is attained.

Comprehensive Bioscreen

For lab testing, we use the company Professional Co-op to run a personalized, comprehensive bioscreen through blood and urine. Although our office does not accept insurance at the time, as a courtesy, we are able to provide superbills to submit for reimbursement or that can work towards your deductible- this applies to lab testing as well! In our private practice, we recommend several markers for patients to gain insights that are key to guiding their care:


We also use RupaHealth, who partners with over 30+ labs to provide thousands of tests, for specialty testing and run personalized panels. This platform offers a wide range of laboratory tests covering various aspects of health and wellness, including hormone balance, digestive health, immune function, cardiovascular markers, and more. These tests are carefully curated from reputable laboratories and cover both conventional and functional medicine approaches, allowing individuals to gain a deeper understanding of their health from multiple perspectives. To view our RupaHealth labshop, check here!

When structuring and personalizing treatment plans for for my patients, looking at labs through a functional medicine lens can help provide just the objective data we need to optimize the system and prevent disease. is one of the filters that I typically bring my patients through, and the information that we collect can help determine the best foods for them to eat and supplements to take. Before making these specific recommendations, I look at these four factors:

  • Blood, Nervous System and Genetic Typing
  • Systemic Imbalances found through Functional Medicine Lab Testing
  • Eastern and Western Medical Basics
  • Your personal preferences and reality

For more information about this, feel free to check our article on diet personalization right here. After receiving the initial lab results, we can always dive into deeper testing as we personalize treatment and tailor it along the way.

Comprehensive Bioscreen: Add-Ons

Allergen Profiles, IgE & IgG (blood test)

When someone has a food allergy, their immune system produces something called immunoglobulin E (IgE) antibodies in response to the consumption of certain foods. This response is usually immediate and these IgE antibodies may cause the skin to break out into hives, wheezing, vomiting and other allergic reactions such as throat tightening. When someone has a delayed food allergy, these are immunoglobulin G (IgG) antibody reactions. These delayed food allergies are often called food sensitivities. With IgG reactions, your immune system produces IgG antibodies that can lead to inflammatory processes and the symptoms can appear up to three day after the consumption of particular problem foods. It is harder to identify exactly which foods cause problems because of the delayed responses, but testing and trying an elimination diet may help. For more on IgE and IgG food allergies, check our article here!

Celiac Disease, Complete Panel (blood test)

Celiac disease is an autoimmune disorder characterized by an inappropriate immune response to gluten (a protein found in wheat) and related dietary proteins in rye and barley. Celiac disease antibody tests help diagnose and monitor this disease along with a few other gluten-sensitive conditions in people with signs and symptoms including anemia and abdominal pain. These tests detect autoantibodies in the blood that the body produces as part of its immune response. For more on celiac disease antibody tests, check here.

Epstein-Barr Virus (EBV) Antibody Test (blood test)

The EBV test is to help diagnose infectious mononucleosis. EBV is a virus that typically causes an infection that is very common, resulting in mild to moderate illness. According to the CDC, most people in the United States are infected by EBV at some point in their lives. This virus is highly contagious and easily passed from individual to individual. It is present in the saliva of infected individuals and can be spread through close contact such as kissing and through sharing utensils/straws/cups/etc. Several tests for different types and classes of EBV antibodies are available. The antibodies are proteins produced by the body in an immune response to several different Epstein-Barr virus antigens. During an initial EBV infection, the level of each of these EBV antibodies rises and falls at various times as the infection progresses. Measurements of these antibodies in the blood can help in diagnosis and typically provides the healthcare provider with information about the stage of infection and whether it is a current, recent, or past infection. For more on the EBV antibody test, check here.

MTHFR, DNA Analysis (whole blood or buccal swab kit)

The MTHFR gene provides instructions for making the MTHFR enzyme, which is involved in the conversion of homocysteine to methionine, a process crucial for DNA synthesis, repair, neurotransmitter production, and detoxification. This conversion requires folate and other B-vitamins as cofactors. Therefore, any variations in the MTHFR gene can impact this essential biochemical pathway. For more on the MTHFR gene and its mutations, check our article right here. For more on the MTHFR test itself, check here.

Prostate Specific Antigen (PSA) (blood test)

Prostate specific antigen (PSA) is a type of protein produced by cells in the prostate. The prostate is a small reproductive gland that helps make semen, the fluid that transports sperm from the testicles through the penis during ejaculation. Healthy prostates create low levels of PSA. An elevated level of PSA may indicate a problem with the prostate. A PSA test can determine if you have high levels of PSA in your blood. Normally, PSA is produced and released within the prostate gland, where it helps make semen and plays an important role in fertility. Only small amounts of PSA move out of the prostate and into the blood in healthy people, but several prostate conditions can cause higher levels of PSA in the blood. For more information on the PSA test, check here.

SARS-CoV-2 Semi-Quantitative Total Antibody (COVID-19), Spike

On May 19, 2021, the FDA issued a safety communication reiterating that “antibody testing should not be used to evaluate a person’s level of immunity or protection from COVID-19 at any time, and especially after the person received a COVID-19 vaccination.” Visit here for more information about the FDA’s statement. For more on the antibody test, check here.

Zinc (blood test)

Zinc is one of the most common minerals found in the human body and is considered an essential mineral because the human body cannot produce it on its own. Most people with underlying health conditions do not get enough zinc through their diet and some people may need supplementation to provide optimal amounts. This test is to monitor exposure to zinc in the body. If an individual is suspected of a nutritional deficiency (especially in enteral or parental nutrition, critically ill patients, cases of diabetes or delayed wound healing, growth retardation, etc.), then a practitioner may recommend testing zinc levels. For more information, check here.

Organic Acids Test (OAT) (urine test)

We also recommend and use Mosaic Diagnostics for ordering the Organic Acids Test. Here is more information about the OAT, which also includes a sample report. An Organic Acids Test offers a comprehensive metabolic picture of an individual’s overall health by providing an accurate evaluation of intestinal yeast and bacteria. Abnormally high levels of microorganisms can cause or worsen behavior disorders, hyperactivity, movement disorders, fatigue, immune functions, and more. Many people with chronic illnesses and neurological disorders often excrete several abnormal organic acids in their urine and these high levels could include oral antibiotic use, high sugar diets, immune deficiencies, acquired infections, as well as genetic factors.

Organic acids are chemical compounds that are released in the urine of mammals that are products of metabolism (the sum of chemical reactions in living beings by which the body builds new molecules and breaks down molecules to eliminate waste products and produce energy). If abnormalities are found using the Organic Acids Test, treatments can include supplements or dietary modifications. Upon making these changes, many patients have seen improvements such as decreased fatigue, regular bowel functions, increased energy, concentration and alertness, improved verbal skills, decreased abdominal pain, and more.

Four Point Cortisol Test

We also recommend and use Doctor’s Data’s for ordering the four point cortisol test. This test is a non-invasive saliva test that measures your cortisol levels four times throughout the day- once when you wake up, once around 10-12, once between 2-4 pm, and once before bed. Cortisol is a hormone produced by the adrenal glands that helps regulate the body’s response to stress. It also helps to regulate metabolism, immune system function, and blood pressure. Healthy cortisol levels are typically high in the morning and slowly come down throughout the day.


Specialty Lab Considerations

For more on our specialty lab selection, you can view our RupaHealth labshop here. Here, we house our favorite specialty labs where we can gain deeper insight into hormones, gut health, nutrient levels, toxic exposure and more. Listed below are four of my most common orders.

Genova Diagnostics GI Effects Comprehensive Profile (stool test)

This test is a group of advanced stool tests that provide immediate information for the management of gastrointestinal health by offering insight into digestive functions, intestinal inflammation, and the intestinal microbiome. Their detailed reports will show “functional imbalance scores” that can help direct therapeutic recommendations with support options. Biomarkers are split into the categories of: maldigestion, inflammation, dysbiosis, metabolite imbalance, and infection. Genova has been the first labratory to introduce an Inflammation-Associated Dysbiosis score and a Methane Dysbiosis score by using published microbiome data analysis. To find out more information about the GI Effects Comprehensive Profile, check here.

DUTCH Hormone Testing (urine test)

The DUTCH test stands for Dried Urine Test for Comprehensive Hormones. This test is done by measuring small amounts of urine on filtered paper four times a day. The DUTCH TEST measures hormone metabolites from the dried urine samples. The DUTCH test measures reproductive and adrenal hormones as well as melatonin and oxidative stress. The hormones measured in the test include:

  • Cortisol
  • Cortisone
  • Estradiol
  • Estrone
  • Estriol
  • Progesterone
  • Testosterone
  • DHEA
  • Melatonin

Genova Diagnostics Metabolomix+ (urine test)

The Metabolomix+ is a comprehensive test that looks at 93 nutritional biomarkers in your body to help identify any potential nutritional deficiencies or imbalances. Add-ons are also available for genetic testing and toxicity screening. For more information, check here.

Doctor’s Data Hair Elements (hair test)

The Hair Elements profile is a noninvasive test that requires only a small sample of your hair. It looks at over 44 different markers and can help identify recent and ongoing exposure to toxic metals and provide information about the status of nutrient elements in your body. For more information on this test, check here.


We Recommend A Comprehensive Bioscreen Annually

In my practice, as a general rule of thumb, I recommend checking in on your biomarkers through our personalized version of a comprehensive bioscreen, that consists of advanced biomarkers, annually so we can note progress and imbalances. This objective data helps us to edit towards your goals as we optimize your treatment plan so you can feel your very best. These valuable insights can help us catch issues before they become problems and stay laser focused as we move forward with confidence and a plan. They can also be a great tool for making sense of symptoms and tracking progress along the way!


More Resources

Resources From Dr. Brooke Stuart / Let Go & Grow®

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