By: Megan Kilmartin (intern) and Orli Rabin of ThrivingBiome
Blood tests can identify abnormalities, assist in disease diagnosis and management, and are essential in preventative care.1 They can also help understand the cause of unexplained symptoms such as fatigue, weakness, brain fog, hair loss, etc.1
Diagnoses can be determined using blood testing or can assist in finding a diagnosis. The blood provides a wealth of information if we can understand how to analyze results.
Ideally, standard reference ranges for conventional medicine are based on a population that is healthy and will provide an accurate representation of a healthy range for a specific biomarker. 2 Statistically, the reference interval is set to describe the measured values of 95% of the population, with the upper and lower percentiles (2.5th percentile and 97.5th percentile) reflecting the small portion of the population that is healthy yet sits at values beyond the accepted range.2 This is commonly known as a bell shaped curve.
Unfortunately, there are limitations to the establishment of this standardized reference range that physicians utilize. For one, the reference interval was established in 1969 by Gräsbeck and Saris, and their goal was to improve lab ranges used by doctors. 3 These ranges are considered outdated as they have not been updated since they were established. Data for some biomarkers, such as vitamin D, shows that the reference range (30-100ng/mL) is normal for what is actually considered deficiency.
This is problematic, because when the conventional ranges are used, even a result of 30ng/mL will not be flagged (even though clinically and based on newer data, anything below 40ng/mL is considered a deficiency). Vitamin D serves as an example of how the use of conventional reference ranges risks early identification of disease or complications.
Due to the challenge presented by standardization across federal hospitals, cost to switch laboratory systems and clinical guidelines, and changes in public health policies, adjusting reference ranges to a more optimal range is often delayed or doesn’t happen. Although the evidence exists that more optimal ranges exist, political and logistical red tape prevent an easy and quick shift in these ranges. Researchers do, however, frequently create new reference ranges based on a reference population for their studies to use as a more reliable comparison. 3 Additionally, the reference ranges were historically based on primarily white males at various ages, which provides misinformation regarding other ethnicities and specific ages as biomarkers vary with age, sex, ethnicity, and even location. 3 Another limitation is that not all biomarkers are accurately represented by the bell shaped curve that covers 95% of the population. 3 For some biomarkers, the data may be skewed, meaning the most common value is not at the midpoint of the curve. Triglycerides are an example of this because commonly triglyceride values are at the lower end of the accepted reference range.2 This implies that the bell shaped curve may not be the most appropriate representation of what a healthy range of biomarkers looks like. The image in Figure 1 depicts how the data is skewed from the typical 95% data range.
Doctors use these reference ranges to determine if biomarkers are abnormal, but fail to consider what is optimal for the body’s health.5 Even at the earliest stages of disease biomarker values can be “normal” and within the accepted range.5 Tracking biomarkers in this manner and only flagging as an issue when falling outside this broad reference range overlooks the importance of patterns at the cellular level.5 These patterns are a window into the optimal functioning of the body and of an individual’s health.
Figure 1: Triglycerides do not align with the standard bell curve, meaning that the 95% interval (area under the red line) used for reference ranges are not the most accurate representation of ideal levels. Reference: Whyte MB, Kelly P. The normal range: it is not normal and it is not a range. Postgrad Med J. 2018;94(1117):613-616. doi:10.1136/postgradmedj-2018-135983
Thankfully, there is an alternative approach to reference ranges. Functional practitioners focus on a narrower range of data, which are described as optimal lab values or optimal ranges. 5 In contrast to the reference ranges that show only a snapshot of these biomarkers, optimal ranges go deeper to show the patterns of biomarkers over time.5 Tracking these patterns can help health care providers identify potential complications and health issues before the disease develops.5 Using this smaller reference range is a functional practice that values optimal functioning of the body. Understanding that “normal” is not equivalent to “optimal” is key for functional practice because there may be issues while exhibiting “normal” blood test results.
Complete Blood Count (CBC): One of the most common blood tests completed that measures red blood cells, white blood cells, and platelets.6 Abnormal levels of red and white blood cells can indicate a variety of things, including anemia (low red blood cell), suggest the presence of heart/lung diseases (high red blood cell), target an immune response (high white blood cell), or indicate autoimmune disorders or infection (low white blood cell). 6 This panel also measures hematocrit levels in terms of percentage of red blood cells in the blood. A CBC will also measure hemoglobin, the iron-containing protein found in the blood that transports oxygen to the body and removes carbon dioxide to be exhaled.6
A CBC can be used to test for Chron’s disease and colitis. Red blood cells transport oxygen and nutrients through the bloodstream to the rest of the body.7 Since hemoglobin carries oxygen throughout the body, both red blood cells and hemoglobin levels are tested in a CBC. Low levels of either or both may indicate anemia, malnutrition, or excessive blood loss. Those with IBD typically have intestinal inflammation that may cause bleeding and can also interfere with proper absorption of nutrients such as iron (anemia).7 White blood cells are important for the immune system response because they provide antibodies that target infections. There are five different types of white blood cells, and each has a different yet crucial role in preventing disease and infection.7 Excessive levels of white blood cells in the blood can suggest infection or inflammation in the body. Again, this could impact the absorption of nutrients as well as point to a gastrointestinal issue.7
A CBC can be used to test for Chron’s disease and colitis. Red blood cells transport oxygen and nutrients through the bloodstream to the rest of the body. Since hemoglobin carries oxygen throughout the body, both red blood cells and hemoglobin levels are tested in a CBC. 6 Low levels of either or both may indicate anemia, malnutrition, or excessive blood loss. Those with IBD typically have intestinal inflammation that may cause bleeding and can also interfere with proper absorption of nutrients such as iron (anemia). 6 White blood cells are important for the immune system response because they provide antibodies that target infections.6 There are five different types of white blood cell, and each has a different yet crucial role in preventing disease and infection. Excessive levels of white blood cells in the blood can suggest infection or inflammation in the body. Again, this could impact the absorption of nutrients as well as point to a gastrointestinal issue.
Understanding what abnormalities exist will assist dietitians in working with you to create a nutrition plan that targets the root of the issue.
Comprehensive Metabolic Panel-14 (CMP-14): This panel analyzes various proteins, electrolytes, enzymes, and minerals in the body. Bilirubin, albumin, liver enzymes ALT (alanine aminotransferase), AST (aspartate aminotransferase), and ALP (alkaline phosphatase), and total protein levels indicate the functioning of the liver. 8 Blood urea nitrogen (BUN), uric acid, and creatinine levels reflect how effectively the kidneys are removing waste from the blood. 8 Sodium, potassium, bicarbonate, and chloride levels are used to analyze electrolyte balance, which affects acid-base and fluid balance in the body.8
What this panel shows through a functional lens:
The health of your liver is related to the quality and condition of the gut microbiome and proper functioning of absorption of nutrients through the intestinal lining.9 IBD, Celiac disease, some infections, and other conditions can damage the integrity of the intestinal barrier and prevent uptake of necessary nutrients or allow passage of harmful substances that could damage the liver.9 By identifying abnormalities in the CMP-14 panel, assessing the health of the liver, identify alterations in the composition of the gut microbiota, and the overall health of the gastrointestinal tract.
Bilirubin is a byproduct of the breakdown of red blood cells. Abnormal levels of bilirubin (high or low) suggest dysfunction of the liver while low levels, specifically, indicate iron deficiency anemia. Albumin is a protein produced in the liver and reflects the health of the liver. Low levels indicate complications in the liver and issues with digestion. Albumin also maintains osmotic pressure to regulate fluid balance and acts as a carrier protein to transport substances throughout the body. Low levels of albumin can be indicative of edema while high levels of albumin suggest dehydration, kidney dysfunction, and/or poor nutrient utilization. The ALT enzyme is found in the liver and is involved in energy production and blood tests measures chronic cellular damage. Low levels suggest liver dysfunction and deficiency in zinc or vitamin B6 while high levels indicate liver disease or inflammation. The AST enzyme is found in the liver, heart, kidneys, and other organs and is used to assess more acute cellular damage/injury. Low levels of AST point to deficiencies in zinc or vitamin B6 and excess levels indicate liver stress. ALP, produced in the liver and bone, assesses liver and adrenal function and can identify dietary insufficiencies and zinc status. Low levels could suggest under eating, low phosphate, zinc, or vitamin B6 deficiencies, or anemia or celiac. High levels could be due to liver issues, hyperthyroidism, and pregnancy. Total protein is the total available protein in the body and is involved in immune defense and maintains osmotic pressure, reflecting pH balance and dietary intake. Low levels point to malnutrition, dehydration, chronic inflammation, and is often low following surgery. High levels could be result of liver stress as well as dehydration or chronic inflammation.
BUN is a byproduct of protein metabolism that is produced in the liver and removed through the kidneys. This component reflects liver and kidney function. Low levels can indicate protein insufficiency, malabsorption, or overhydration while excess levels result from diets high in protein, hyperthyroidism, dehydration, and kidney dysfunction. Uric acid is a byproduct of protein breakdown and is excreted via the kidneys. A low uric acid status can indicate low protein intake or poor absorption, and high levels suggest stress in the kidneys and a high intake of protein. Creatinine is a byproduct of muscle tissue breakdown that is excreted by the kidneys similar to BUN and uric acid. Creatinine levels reflect the amount/intensity of physical activity of the individual. Low levels are indicative of inadequate activity and protein intake and a low protein intake in the diet. Excess levels point to kidney issues and may suggest hyperthyroidism and dehydration. Creatinine levels may sometimes be elevated in athletes who workout more intensely.
The most abundant extracellular electrolyte is sodium and is a reflection of hydration status, kidney and adrenal function, and pH balance. Insufficient intake, diarrhea, kidney dysfunction, and excessive sweating can lead to low levels of sodium. Dehydration, water retention, excessive intake, congestive heart failure, and overactive adrenals can cause excess levels of sodium in the blood.
Potassium is the most abundant intracellular electrolyte and plays key roles in the acid-base balance, muscle and heart contraction, nerve function, and is influenced by the functioning of liver and adrenals. Low levels indicate hypertension, nutritional deficiencies, or hypertension, and high levels could be due to over supplementation, kidney issues, or other complications. Bicarbonate serves as a buffer in the blood that affects pH balance. Kidney disease and diarrhea can cause low levels of bicarbonate in the blood.10 When vomiting continues long term or kidneys are not functioning optimally, bicarbonate levels can be high.10 Chloride, the most abundant extracellular anion, assists in maintaining fluid balance and regulates the flow of fluid across the cell membrane. Low levels can be caused by excessive sweating, overhydration, IBD, hypokalemia, and can lead to feelings of tiredness. High levels of chloride suggest dehydration, anemia, tissue swelling, or Cushing’s disease.
Mineral levels in the body tend to be “fragile” as they are influenced by various intrinsic and extrinsic factors. Levels can be affected by many intrinsic and extrinsic factors, including age, fluctuation in hormones, excessive sweating, sickness, dehydration, and medication. A more thorough and complete picture of these levels can come from an HTMA test, which provides an overview of these levels over the course of several months.
Additional micronutrients/mineral tests: Assessing mineral levels assists in finding possible excesses and deficiencies, both of which can lead to adverse health reactions. Minerals assist in regulating and supporting essential processes such as muscle contraction, forming various enzymes and hormones, and proper functioning of the immune and nervous system.
Vitamin A (retinol) promotes eye health and a properly functioning immune system, and regulates proper usage of copper in the body. Low levels could suggest inadequate intake of vitamin A, fat malabsorption, or liver stress while high levels could be caused by over supplementation or use of topical creams with a base containing vitamin A. Vitamin D, 25-Hydroxy regulates immune health and hormone functioning. Low levels can indicate reduced sun exposure, a vegan or vegetarian based diet, malabsorption of nutrients, or deficiency of magnesium. High levels could be due to over supplementation or prolonged antacid use. Magnesium is an intracellular electrolyte that affects heart contraction, ATP production, and supports functioning of insulin. Lower than normal levels of magnesium can indicate either malnutrition or malabsorption. Higher than normal levels can be due to antacid use, elevated albumin levels, or underactive thyroid or adrenal functioning. Zinc is important for immune function, DNA repair, and functioning of neurotransmitters. Low levels of zinc suggest gastrointestinal complications such as malabsorption, a vegan or vegetarian diet, infection or inflammation. Over supplementation can lead to excess levels of zinc in the blood. Copper assists in the production of red blood cells, the formation of collagen, neurotransmitter function, and is involved in the proper use of iron. Low levels of copper indicate excessive supplementation of zinc, but high levels suggest a vegan or vegetarian diet, deficiency of zinc, and could be due to various environmental exposures. Ceruloplasmin is a protein produced in the liver that binds and transports copper. Reduced amounts of this protein can cause copper toxicity while causing low amounts of bioavailable copper at the same time. Low levels point to liver stress and zinc or vitamin A deficiency. Levels above normal can be caused by pregnancy and hormonal contraceptives or can be due to copper toxicity. Adequate levels of ceruloplasmin is essential for the release of iron from the body’s stores to be used by tissues.
Iron Panel: The iron panel traditionally measures iron and proteins related to iron metabolism in the body. These include transferrin, the protein that binds iron and transports it throughout the body; ferritin, which stores iron in tissues; total iron-binding capacity (TIBC), which measures how much iron transferrin can carry; and hemoglobin, which reflects the oxygen-carrying capacity of red blood cells. In conventional medicine, physicians often focus on ferritin and hemoglobin values. When these fall outside standard reference ranges, iron supplements are frequently prescribed without considering the broader context.
However, supplementing with iron inappropriately can worsen symptoms such as fatigue, achy joints, shortness of breath, rapid heartbeat, and hair loss, especially when the underlying issue is not iron deficiency but a dysfunction in iron transport, storage, or metabolism. That’s why we often advocate for a more complete assessment, sometimes called the “full monty iron panel.” This expanded panel includes transferrin, ferritin, hemoglobin, and TIBC, but also assesses additional biomarkers such as vitamin A, ceruloplasmin, and copper. These markers are crucial for understanding how iron is actually used and regulated in the body. A deficiency in any of them can mimic or contribute to symptoms of iron deficiency, even when iron levels are sufficient.
Iron is essential for numerous biological functions. The body uses iron to support red blood cell production, immune system function, energy metabolism, and DNA synthesis. According to current dietary guidelines, the recommended daily intake of iron is 8 mg for adult men and postmenopausal women, 18 mg for premenopausal women, 27 mg for pregnant women, and 9 mg for lactating women. While these values help guide intake, they do not reflect how much iron the body is actually using each day (read more on this below in the iron recycling system section).
Given the amount recycled daily, these levels are typically sufficient unless there are dietary restrictions or increased blood losses. However, nutrient deficiencies, patterns of under-eating or over excretion of nutrients, and plant-based diets can interfere with iron status as well. This reinforces the need for diverse and nutrient-rich diets containing both macro- and micronutrients, rather than relying solely on supplements to correct imbalances. When iron-rich foods are consumed, the nutrient is absorbed through the intestinal wall. Heme-iron has higher bioavailability than non-heme iron meaning the body more readily absorbs iron in this state.11 Heme-iron can be found in animal products, while non-heme iron is found in plant based foods and needs to be converted to the heme-iron state (ferric state) to be used effectively.11
The majority of daily iron needs—about 95%—are met through the iron recycling system, which produces approximately 24 mg of iron every 24 hours. In fact, only 5% of daily iron is typically absorbed from the diet. This system is vital for maintaining homeostasis and reducing reliance on dietary iron alone. Stored iron, primarily found in ferritin, is released when needed and reused for essential functions such as oxygen transport, enzyme activation, and immune defense.
A key regulatory component of this recycling system is hepcidin, a liver-derived hormone that controls iron absorption and release. When iron stores are sufficient, hepcidin levels increase, which inhibits the iron exporter ferroportin and blocks further iron absorption from the gut and release from cells. When iron levels are low, hepcidin levels drop, allowing ferroportin to release iron from storage and enhance absorption from the diet.
Once iron is released from storage, it is in the ferrous (Fe²⁺) state. To be transported in the bloodstream, it must be converted to the ferric (Fe³⁺) state by the enzyme ceruloplasmin. In its ferric form, iron binds to transferrin, which carries it to tissues where it is needed. If ceruloplasmin, or its required cofactor bioavailable copper, is deficient, this conversion cannot occur efficiently, and iron may build up in tissues rather than being used effectively—leading to symptoms that resemble iron deficiency.
The recycling system is not only efficient but protective. Free iron, which is not bound to transferrin, can promote inflammation and serve as a nutrient source for pathogens. To prevent this, excess iron is safely stored in ferritin. However, some pathogens release cytotoxins that damage cells and trigger ferritin release, contributing to inflammatory conditions. Elevated ferritin levels, therefore, may not always indicate sufficient iron but instead reflect underlying inflammation or cell damage.
From a functional perspective, iron status cannot be evaluated in isolation. The “full monty” panel provides insight into the entire iron recycling system by examining not only standard markers (iron, ferritin, hemoglobin, TIBC) but also the nutrient co-factors and regulatory proteins involved in absorption, transport, and utilization.
The iron recycling system involves each biomarker, and each has a role in the regulation of iron balance in the body. For example, copper is a critical cofactor for ceruloplasmin, an enzyme required to oxidize iron from the ferrous (Fe²⁺) to the ferric (Fe³⁺) state, which allows transferrin to bind and transport it. Without enough ceruloplasmin, iron cannot be released from storage properly and may accumulate in tissues, creating a false appearance of deficiency despite adequate total body iron. This is why bioavailable copper—the form the body can actually use—is essential. In turn, vitamin A (retinol) supports ceruloplasmin expression, meaning that low vitamin A can indirectly cause iron dysregulation. Zinc can interfere with copper absorption and promote its excretion, further complicating the balance.
Additionally, vitamin C enhances non-heme iron absorption (from plant-based sources). Consuming iron-rich foods alongside vitamin C sources increases the bioavailability of dietary iron, making food pairings a key strategy in nutrition planning.
Understanding this full cascade—from intestinal absorption to oxidation, transport, and storage—clarifies why symptoms like anemia may not improve with iron supplementation alone. If hepcidin is high, the body will block iron absorption no matter how much is consumed. If ceruloplasmin or copper is low, iron will remain trapped in storage. If inflammation is high, ferritin levels may misrepresent true iron status. Recognizing these relationships allows for more precise, effective, and less harmful treatment strategies.
Hormone and Endocrine tests: Analyzing hormone levels and identifying potential imbalances that could be leading to other health issues. This panel helps find and manage endocrine-related conditions that may affect endocrine glands like the thyroid and pituitary.
Reference Ranges for TSH5
Reference Ranges for T3
Reference Ranges for T4
Reference Ranges for Reverse T3
What this panel shows through a functional lens:
TSH is produced by the pituitary gland and is responsible for stimulating the thyroid gland to release T4 and T3.13 Assessing TSH levels gives insight to how the signaling function of the thyroid pathway is being maintained. The T4 hormone is the inactive and unbound form that is converted to T3, which is the active and carrier-bound protein form that is involved with cell functioning.13 T4 levels are important to understand how effectively the thyroid gland is producing hormones for use. T3 levels indicate how effectively the body is converting these forms of the thyroid hormone. Low levels indicate possible hyperthyroidism or high cortisol causing a negative feedback loop in the hypothalamic-pituitary-adrenal axis. 13 Conversion from T4 to T3 is essential because this active form of the enzyme directly affects energy production and regulation of the metabolism. T3Free and T4Free, the unbound forms of these hormones, circulate the body and enter tissue and cells readily. 13 Upon entering the cell, T4free can be converted to T3 to be used for biological processes. Similarly to their bound forms, T3Free provides a picture of efficiency of conversion while T4Free shows how well the thyroid is producing these hormones. Reverse T3 (rT3) is an inactive byproduct of T4 that is indirectly related to T3 levels, meaning elevated levels of rT3 are often seen alongside reduced T3 levels. This is an energy saving action that is often seen during times of illness, stress or fasting/starvation.13,14
Thyroid hormone levels can be impacted by reverse T3 as this inactive form of the hormone is associated with lowered conversion of T4 into T3.14 T3 levels will also impact iron function because it helps stimulate the liver to make ceruloplasmin. 13 This highlights the interconnectedness of the body’s processes, showing the importance of comprehensive medical panels. TPO and thyroglobulin antibodies give insight to dysfunction in the thyroid and signals if there is an autoimmune disorder present. 13 Elevated levels of these antibodies show an autoimmune response against the thyroid and assists in diagnosing autoimmune thyroid diseases (Hashimoto’s and Grave’s disease). A complete thyroid panel allows for more accurate diagnoses and earlier detection of these autoimmune thyroid dysfunctions, allowing for sooner and more effective intervention. Panels that test for all biomarkers provide a more accurate depiction of the health of the thyroid and is a root-cause driven assessment.
Conventionally, thyroid panels include assessment of TSH, T4, and occasionally T3, T3Free, and T4Free levels in the body. TSH levels alone cannot provide a conclusive picture about the health status of the thyroid as this hormone is produced in the pituitary gland rather than the thyroid itself.15 Including antibodies (TPO) in the comprehensive panel reveal the functioning of the immune system, and can affect the outcome of disease treatment as earlier detection for disease prevents worsening or development of complications. 15 In some cases, TSH levels may even appear normal in a blood panel, but antibody levels suggest otherwise, allowing this earlier detection and intervention that many have found crucial to slow disease progression. A functional approach assesses more than the basics regarding thyroid health and takes time to distinguish and analyze the multiple parts of the thyroid pathway. Testing for other components such as albumin and total protein (discussed in CMP-14 Panel section) are used to assess the efficiency of transporting these hormones, causing a negative downstream effect for other bodily processes. We offer HTMA testing, alongside blood panels, that can help shed light on important co-factors and co-nutrients related to thyroid hormone absorption and utilization. These extra investigative steps allow us to identify where the pathway has become dysfunctional and more accurately find a diagnosis and begin treatment prior to the development of avoidable complications. Thyroid function significantly impacts many of the body’s other processes, including metabolism, reproductive health, mental health, and cardiovascular health. Taking the opportunity to dive deeper into understanding the whole picture of the thyroid function in the body will produce results beyond thyroid health.
The gut-thyroid axis needs to be supported through adequate nutrition and management of gut bacteria.15 As the gut influences immune regulation and micronutrient availability, the impact on thyroid function is evident. Therefore, treatment for thyroid dysfunction could include healing the gut microbiome as well.15 Autoimmune dysfunction can lead to other thyroid conditions (Hashimoto’s disease), and identifying triggers in the environment and diet can ease symptoms. Additionally, reducing stress on the body can impact gut health as well as thyroid function as inflammation and stress can negatively affect thyroid hormone production. 15
Reference Ranges for Hgba1c (percentage point)5
Reference Ranges for Fasting Insulin
Reference Ranges for Fasting Glucose
Lipid panel: This test measures the amount of fat (lipid) in the blood. The panel assesses five types of lipids, including low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), high-density lipoprotein (HDL), triglycerides, and total cholesterol.16 LDLs, commonly known as “bad” cholesterol, moves cholesterol through the body via the bloodstream and is used for cell repair and cell membrane formation.16 Excess levels can lead to plaque build up in the arteries, increasing risk of cardiovascular diseases. 16 VLDLs are needed to deliver triglycerides to tissues and are used in energy storage among other functions. HDLs, known as “good” cholesterol, work to reduce the amount of LDL cholesterol found in the bloodstream. 16 These lipoproteins lower risk of cardiovascular diseases. Triglycerides are used for energy storage, but excess amounts in the body can lead to heart disease or stroke.16
Inflammatory markers: These blood tests measure the proteins that increase during periods of inflammation in the body. The tests include C-reactive protein (CRP), high-sensitivity CRP, and erythrocyte sedimentation rate (ESR). Inflammatory markers help point physicians in the right direction when making a diagnosis.
Blood tests and gut health
Blood testing can be used to identify and diagnose digestive conditions by analyzing components of the blood. 17 Celiac disease, inflammatory bowel Disease (IBS), food allergies, and ulcers of the stomach can be diagnosed with help of blood test analysis.17 By honing in on specific components of the blood, more effective treatment plans can be used.
Individuals who have celiac disease often experience micronutrient deficiencies at the time of their diagnosis. 18 Sometimes, these deficiencies can help guide physicians towards a celiac diagnosis. Deficiencies that are common in celiac patients include iron, folate, vitamin B6 and B12, vitamin D, copper, and zinc.18 This often occurs because the damaged intestinal walls are unable to adequately absorb nutrients for use in the body. Those with celiac disease may also see heightened levels from the C-Reactive protein, High Sensitivity blood test due to the inflammation caused by the autoimmune disease.18
While these tests can help point towards a diagnosis, they are not enough to diagnose celiac disease.18 Celiac panels can be used to make the diagnosis, which includes a tTG-IgA, EMA-IgA, DGP-IgA and DGP-IgG tests. 18 Testing for these antibodies can indicate if the immune system is undergoing an adverse reaction to gluten. Heightened levels would be sufficient for a diagnosis of celiac disease. 18
Blood tests and genetic mutation relevant to nutrition
Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that is essential for converting folate to methylfolate, its active form, and processing homocysteine (an amino acid) and converting it to methionine, an essential amino acid.19 Mutation of this gene causes dysfunction of the MTHFR enzyme, which can cause reduction in folate levels and elevated homocysteine levels in the body.19 The downstream effect of elevated homocysteine levels is reduced amounts of methionine. Reduced levels of methylfolate can impact blood cell formation and methylation, a process that regulates gene expression. 19
Since the MTHFR mutation inhibits production of folate’s active form, folate deficiency can develop. Long term, this can lead to folate deficiency anemia, which is characterized by reduced red blood cell production and the presence of red blood cells that are larger and less effective than normal.19 A conventional approach to this deficiency is folate supplementation, in the form of folic acid (the synthetic, shelf stable, cost effective form), however, this can lead to an accumulation of folic acid in the body as the synthetic supplement form is less likely to be converted to the active form for those with this mutation, than folate derived from food products.19 Focusing on folate-rich foods like dark, leafy greens, lentils and legumes, fruits, avocados, and certain types of fortified breads is a better alternative as these sources are more likely to be converted to methylfolate.
The example of the MTHFR mutation highlights the importance of looking at many biomarkers versus just one. Identifying and treating the cause alone doesn’t solve anything and risks the development of more complications. Instead, taking the functional approach and looking at the whole picture and understanding the causes of the deficiency allows us to rectify nutritional imbalances more effectively and safely.
ThrivingBiome uniquely orders the tests highlighted in blue along with the other tests and panels.
Complete Blood Count (CBC) with Differential
Comprehensive Metabolic Panel (CMP-14)
Lipid Panel
Nutritional & Mineral Panels:
*Vitamin A, retinol
Vitamin D, 25-Hydroxy
Magnesium, RBC
Zinc, serum or plasma
*Copper, serum or plasma
*Ceruloplasmin
Iron Studies:
Iron + Total Iron Binding Capacity (TIBC) + Ferritin
Transferrin
Hormone & Endocrine Panels:
TSH + T3Free + T4 Free Reflex to TPO
Reverse T3
*Thyroid Antibodies
Insulin
Liver Function:
Gamma-Glutamyl Transferase (GGT)
Inflammatory Marker:
C-Reactive Protein (CRP), High Sensitivity
*Tests that are starred are those that are not typically recommended by physicians. At ThrivingBiome, we use these tests to get a clearer picture of the function and utilization of these nutrients in the body. Inclusion of these tests allows analysis of the balance of several nutrient’s relationships to assess the root cause of the issue.
There is so much information we can glean from an annual panel, if we just look a little deeper. Many of the body’s functions have interconnected pathways, and when one of these pathways breaks down, there is a negative downstream effect elsewhere in the body. Since many of these functions are dependent on various other biomarkers for proper usage, assessing the values for one biomarker or interpreting results individually rather than a whole causes the details to be missed. As discussed previously, the patterns of these values over time and how they impact one another is the true value behind these blood tests. Blood test results tell a fascinating story about our health if we take the time to understand the message behind the numbers.
References
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3.Timbrell NE. The role and limitations of the reference interval within clinical chemistry and its reliability for disease detection. British Journal of Biomedical Science. 2024;81. doi:10.3389/bjbs.2024.12339
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11.Montalvo A. S4 e7: Iron Deep Dive Part 1. Hormone Healing RD. January 10, 2024. Accessed May 29, 2025. https://hormonehealingrd.com/podcast-episode/s4-e7-iron-deep-dive-part-1/.
12.professional CC medical. TIBC (Total Iron-binding capacity) test. Cleveland Clinic. March 19, 2025. Accessed June 4, 2025. https://my.clevelandclinic.org/health/diagnostics/24979-total-iron-binding-capacity-tibc.
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14.Reverse T3 (RT3) [blood]. BeFunctional Labs. Accessed June 8, 2025. https://www.befunctional.com.au/functional-tests/thyroid-hormones/reverse-t3-rt3-blood.
15.Christie J. Why do functional medicine practitioners prefer to order comprehensive thyroid panels? Rupa Health. January 14, 2025. Accessed June 8, 2025. https://www.rupahealth.com/post/why-do-functional-medicine-practitioners-prefer-to-order-comprehensive-thyroid-panels#:~:text=Why%20Practitioners%20Choose%20Complete%20Thyroid,of%20life%20for%20our%20patients.
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