10 Most Important Functional Blood Chemistry Tests For You

Written By


Expert Reviewed By

Dr. Lauryn Lax, OTD, MS

Dr. Lauryn, OTD, MS is a doctor of occupational therapy, clinical nutritionists and functional medicine expert with 25 years of clinical and personal experience in healing from complex chronic health issues and helping others do the same.

Functional Blood Chemistry

What kind of lab test should I get? A functional blood chemistry panel is the most comprehensive type of blood chemistry test you can get at your doctor’s office to give you the best picture of how healthy you really are.

Functional Blood Chemistry Panel vs. Conventional Blood Chemistry Panel

Functional Blood Chemistry

When you go to your doc for a check up and they take blood, they typically will run a general “wellness” conventional blood test panel, consisting of approximately 10-15 lab markers including Red & White Blood Cell count, Cholesterol, Serum (blood) hormones, and Fasting Glucose.

While these blood markers ARE part of a picture of your overall health, a functional blood chemistry panel provides a much more comprehensive look at what is REALLY going on “under the hood.”

3 Essentials of a Functional Blood Chemistry Panel

#1: Functional Blood Chemistry Looks at the BIG Picture

Functional blood chemistry panels evaluate approximately 50+ different blood markers that play a role in detecting a variety underlying health imbalances and conditions, including:

  • Hyperglycemia & Hypoglycemia (High blood sugar & low blood sugar)
  • Impaired kidney function
  • Impaired liver function
  • Dehydration & electrolyte imbalances
  • Gout
  • Muscle mass (loss or gain)
  • Impaired gallbladder function
  • Iron deficiency & iron overload
  • B12 deficiency
  • Anemia (Iron or B12/Folate related)
  • Cholesterol & heart disease
  • Blood sugar balance
  • Thyroid function (hypo- or hyper- thyroidism)
  • Viral & bacterial infection
  • Cancer
  • Allergies
  • Vitamin D deficiency or toxicity

#2: Functional Blood Chemistry Lab Ranges are Narrower

Additionally, a functional blood chemistry panel includes functional lab ranges that are MUCH TIGHTER and narrower than the conventional blood lab panel lab range “norms” you get in your report through your general practitioner’s office.

#3: Functional Blood Chemistry Considers Lifestyle Factors & Total Health

Lastly, functional blood chemistry considers MORE than just lab results alone.

Functional blood chemistry is never used in isolation. It is always combined with a thorough review of a patient’s medical history, current symptoms, and consideration of diet and lifestyle, medications and supplement factors.

For example, a patient’s blood test results may show decreased serum iron levels.

While a conventional blood chemistry may automatically assume that the patient is anemic and prescribe iron supplementation to “improve levels,” a functional blood chemistry review considers other things like:

  • Do they have celiac disease or gluten intolerance?
  • Is it actually a B12/Folate deficiency?
  • Are they taking PPI drugs (acid suppressing drugs)?
  • Do they have insulin resistance or blood sugar imbalances?
  • Are they menstruating regularly?
  • What are their OTHER iron markers showing (UIBC, TIBC, ferretin)
  • If they are, the elevation is simply a sign of that, and it’s nothing to worry about.

Other markers of health and questions can help the clinician determine the reasons behind  blood markers and body imbalances.

Case Studies: Functional vs. Conventional Blood Panels

Example 1: Thyroid Levels

For instance, the range for “healthy” TSH (thyroid hormone) levels is:

  • Functional Blood Chemistry TSH Range:  0.5-2.0vs.
  • Conventional Blood Chemistry TSH Range: 0.45-4.50

Why this matters?

If a patient was to be experiencing common symptoms of hypothyroidism, such as unwanted weight gain, general fatigue, feeling cold easily or hair loss, but they go to their conventional doctor and get a TSH lab reading of 3.5 or 4.0, the doc may tell them it’s on the “higher end of the range,” but it is nothing to worry about.

Whereas if a patient with the same symptoms was to get a functional blood chemistry lab panel through their functional medicine or healthcare provider, the provider could then direct them into looking further into the underlying conditions/reasons driving their symptoms—such as HPA-Axis function (cortisol and hormone levels and stress), gut health function and Vitamin D markers.

Instead of passively waiting for the TSH levels to reach 4.5+ and THEN diagnose the patient with “hypothyroidism,” the functional blood chemistry panel allows us to catch disease early in the progression stage.

Example 2: Diabetes

Another example, say that another patient gets a functional blood chemistry panel and their practitioner detects that they are in the early stages of developing type 2 diabetes.

This EARLY detection would allow them to direct the patient to make a few simple dietary and lifestyle changes in order correct their metabolic dysfunction without ever taking a single medication or supplement.

Whereas with the conventional blood chemistry panel, Type 2 Diabetes is typically not detected until it is fully manifested.

In fact, by this point, it may be so far into the disease that the patient requires several medications, including insulin in order to manage it, as well as other serious and expensive complications such as kidney dysfunction and glaucoma, requiring additional medications or hospitalization.


Functional Blood Chemistry

Functional blood chemistry is ALL ABOUT catching disease or imbalances BEFORE they have progressed to a full range of symptoms and the side effects of a disease. 

Conventional blood chemistry lab ranges, on the other hand, are much broader. Thus if your conventional blood markers fall within this broad range of norms, a conventional blood chemistry panel may make you believe that your poor health imbalances and side effects are “normal.”

A functional blood chemistry panel is one of the most efficient and effective screening tools available for both patients and clinicians. It allows us to quickly assess the function of some of the most important body systems, identify current problem areas, and detect potential problems that, if left unaddressed or untreated, may become significant and even life-threatening problems in the future.


So where do you even begin?

Here’s an idea of some common blood chemistry health markers, compared to functional blood chemistry, and what to look for when you get your next blood test.

[fusion_accordion type=”” boxed_mode=”” border_size=”1″ border_color=”” background_color=”” hover_color=”” divider_line=”” icon_size=”” icon_color=”” icon_boxed_mode=”” icon_alignment=”” hide_on_mobile=”small-visibility,medium-visibility,large-visibility” class=”” id=””][fusion_toggle title=”Glucose (mg/dL)” open=”no”]

Functional: 75-85

Conventional: 65-99

What if it’s high out of the functional range?

  • Early stages of impaired glucose tolerance and insulin resistance
  • Active stress response

What if it’s low, out of the functional range?

  • Reactive hypoglycemia
  • Hypoglycemia (may still be present when glucose is above 65)
  • Impaired liver function

[/fusion_toggle][fusion_toggle title=”BUN (mg/dL)” open=”no”]

Functional: 13-18

Conventional: 6-24

What if it’s high out of the functional range?

  • Mild dehydration
  • Impaired kidney function
  • Inadequate sodium intake
  • Stress
  • Hypochlorhydria
  • Urinary tract obstruction

What if it’s low, out of the functional range?

  • Impaired liver function
  • Poor nutrient status/malabsorption
  • Celiac disease
  • Hypochlorhydria
  • Anabolic steroid use
  • Impaired kidney function

[/fusion_toggle][fusion_toggle title=”Sodium (nmol/L)” open=”no”]

Functional: 135-140

Conventional: 134-144

What if it’s high out of the functional range?

  • Functional dysglycemia (check other markers of glycemic dysregulation)
  • HPA axis dysregulation (more likely hyperfunction)
  • Cushing’s disease
  • Mild dehydration

What if it’s low, out of the functional range?

  • Functional dysglycemia (blood sugar imbalance)
  • Hypothyroidism
  • HPA axis dysregulation (more likely hypofunction)

[/fusion_toggle][fusion_toggle title=”Potassium (nmol/L)” open=”no”]

Functional: 4.0-4.5

Conventional: 3.5-5.2

What if it’s high out of the functional range?

  • Functional dysglycemia
  • HPA axis dysfunction
  • Impaired kidney function

What if it’s low, out of the functional range?

  • Functional dysglycemia
  • HPA axis dysfunction
  • Malabsorption and malnutrition
  • Alcoholism
  • Medications such as antibiotics or diuretics

[/fusion_toggle][fusion_toggle title=”Vitamin D, 25-hydroxy (ng/mL)” open=”no”]

Functional: 35-60

Conventional: 30.0-100.0

What if it’s high out of the functional range?

  • Excessive supplementation

What if it’s low, out of the functional range?

  • Iron overload
  • Hypothyroidism
  • IBD (Irritable bowel disease)
  • Nonpathological in some nonwhite populations (must check PTH and 1,25D to determine true biological vitamin D activity)

[/fusion_toggle][fusion_toggle title=”WBC (x 103/μL)” open=”no”]

Functional: 5.0-8.0

Conventional: 3.4-10.8

What if it’s high out of the functional range?

  • Metabolic disorders
  • Acute infection (especially bacterial, but also certain viral and fungal infections)
  • Inflammation
  • Chronic inflammatory conditions (e.g., rheumatoid arthritis, Crohn’s disease, ulcerative colitis, vasculitis)
  • Acute stress
  • Certain drugs

What if it’s low, out of the functional range?

  • Nutritional deficiency (e.g., vitamin B12, folate, copper)
  • Infection (e.g., HIV, sepsis)
  • Autoimmunity

[/fusion_toggle][fusion_toggle title=”Cholesterol, total (mg/dL)” open=”no”]

Functional: 150-230

Conventional: 100-199

What if it’s high out of the functional range?

  • Poor thyroid function
  • Intestinal permeability
  • Chronic infections
  • Heavy metal toxicity (and possibly presence of other toxins such as mold)

What if it’s low, out of the functional range?

  • Metabolic disorders
  • Anemia
  • Chronic inflammation
  • Infection (acute or chronic)
  • Hyperthyroidism
  • Chronic liver disease
  • Sickle cell disease
  • Malabsorption and undernutrition (e.g., critical illness)
  • Statin drugs

[/fusion_toggle][fusion_toggle title=”Triglycerides (mg/dL)” open=”no”]

Functional: 50-100

Conventional: 0-149

  • What if it’s high out of the functional range?
    Non-fasted state (make sure patient was fasting)
  • Early insulin resistance
  • Hypothyroidism

What if it’s low, out of the functional range?

  • Malabsorption
  • Hyperthyroidism
  • Autoimmune disease (some clinicians have empirically noted low triglyceride levels in patients with autoimmune disease)

[/fusion_toggle][fusion_toggle title=”TSH (μIU/mL)” open=”no”]

Functional: 0.5-2.0

Conventional: 0.450-4.50

What if it’s high out of the functional range?

  • Hypothyroidism
  • Iodine, selenium, or zinc deficiency
  • Functional iron overload

What if it’s low, out of the functional range?

  • Facetious hyperthyroidism (excessive thyroid hormone replacement)
  • Pituitary hypofunction

[/fusion_toggle][fusion_toggle title=”T3, Total (ng/dL)” open=”no”]

Functional: 100-180

Conventional: 71-180

What if it’s high out of the functional range?

  • Hyperthyroidism
  • Facetious hyperthyroidism (excess thyroid hormone replacement)

What if it’s low, out of the functional range?

  • Hypothyroidism
  • Inflammation


This is not an exhaustive list. Most functional blood chemistry panels include over 50 markers in order to help clinicians see patterns and trends that hint at certain diseases and imbalances.


Want to get a complete functional blood chemistry panel and health assessment without going to your conventional doctor?

Book an Initial Consult with Dr. Lauryn https://drlauryn.com/work-with-me to help you understand your own health better, and get a custom nutrition, supplement and lifestyle plan built for you to feel amazing—inside and out.

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