Try This: Optimal Lab Reference Ranges Cheat Sheet (Re-Share)

Have you ever made an appointment with your doctor because you’re feeling a little “off” and don’t know why? Maybe you’re dealing with unexplained weight gain, fatigue, low libido, or skin challenges you haven’t experienced until now that you want to get checked out.

So, your doctor gives you a quick physical exam and orders some lab work. You know, the basics: a comprehensive metabolic panel, complete blood count, and lipid panel. Only to come back for a follow-up, hoping for answers to hear your doctor say, “Everything looks great,” or “All your labs came back normal.”

At the most, maybe you’re told to lose weight or start exercising more, and you’re sent on your way. This happens all the time, and if it hasn’t happened to you, I’m sure you know somebody who’s dealt with this. Everything looks good on paper, but you don’t feel good.

Today, we’re talking about optimal lab reference ranges for whole-body health and re-sharing one of our most popular newsletters to date that explains why standard lab ranges aren’t setting us up for long-term health.  We also dive into how to ask your doctor for the lab tests you need and provide your very own cheat sheet of “normal” vs. optimal ranges to compare your lab results to. 

Even if you read this newsletter the first time around, let this be your reminder to make an appointment to get your bloodwork done! Staying on top of your labs is one of the best ways to know what’s going on with your health.

It’s Not Normal To Feel Like Crap

Conventional medicine tends to look at health as an objective, or absolute state—you either have it or you don’t. Even if your lab results come back borderline high or low, often no action is taken to keep it from going in that direction.

As long as your labs fall within the “normal” reference range, it’s assumed that you’re healthy, or at least not sick enough for a medical intervention. So you keep chugging along until you come back a year later only to find your numbers are out of range and action is finally taken, usually with a prescription or referral to a specialist.

Currently, this is how our medical system operates. It takes a “wait and see” approach based on a conventional belief system around health and disease. Don’t get me wrong, modern-day medicine definitely has its place. It saves tons of lives and I’m happy it’s there for emergency situations and tricky medical conditions. However, for some reason, preventative healthcare is not a focal point, and it’s not the fault of doctors—most aren’t taught about it in medical school.

I’m hopeful that one day it will be recognized that most of the chronic disease burden we see today is lifestyle-related and could be prevented and treated using personalized diet and lifestyle interventions.

Until then, because health is looked at in this way, millions of people are walking around feeling like absolute crap. The worst part is, we’ve been totally convinced that this is normal. I’m here to tell you, it’s not normal. And who wants to live life “normal,” anyway? It’s our birthright to be able to thrive while we’re here, and for me, that’s all about living optimally.

Why “Normal” Can Lead To Problems

When we base an individual’s health status on whether or not they fall within a given reference range, it assumes that:

A) Health looks the same on everyone. We know for a fact this isn’t true because genetics, diet, lifestyle, and environment play a huge role in how our bodies function, and our risk for chronic disease.

B) Reference ranges are coming from the average population of adults. But if more than 50% of US adults have at least one chronic disease, and more than 50% are either overweight or obese, are these numbers derived from a population that reflects health, or the absence of disease?

C) Disease is binary (you either have it or you don’t), and this is primarily determined by whether or not a person’s labs fall in or out of a given reference range. We know that this isn’t true.

The problem with this is: chronic disease doesn’t happen overnight. It’s a slow process that takes years, sometimes decades, to develop. You don’t just wake up one morning with diabetes; brick by brick disease is slowly created.

Normal ≠ Optimal

In Functional Medicine, reference ranges are chosen using values representative of optimal health, rather than what’s “normal” based on the average “healthy” population. Optimal reference ranges are also much narrower than what’s used in conventional medicine so any signs of dysfunction can be detected early on, before disease has the chance to develop.

In addition to that, Functional Medicine, Lifestyle Medicine, and open-minded doctors test more than what’s routine. Specific nutrients, hormones, inflammatory markers, enzymes, fasting insulin, and blood lipid subtypes are also tested for, as well as your thyroid and adrenal gland function. Essentially, they are testing for every parameter they can that plays an integral role in our metabolic and overall health.

Unfortunately, we are dealing with a shortage of cutting-edge doctors because they are in high demand. Plus, I know that seeing one can get pretty pricey since most aren’t covered by insurance. The good news is that your primary care doctor can order these same lab tests for you; all you have to do is ask.

Approach Is Everything

When you ask your doctor for the tests I have listed below, it’s important to be mindful of your approach. Doctors can get turned off when patients come in demanding specific lab tests that aren’t their usual level of care—wouldn’t you be a little annoyed if someone came in and started telling you how to do your job?

Although it may not seem fair, your doctor does have the final say, so we want to make sure we are genuine, calm, and polite in our approach. Kindly share that you’re interested in working together as a team. Explain that you want to take the steps necessary to reduce your risk for disease so that you can live the longest, healthiest, and best life possible.

Express your excitement in learning about these lab tests, and gratitude and appreciation for working with a practitioner who can order them for you. If your doctor isn’t open-minded, that’s okay. There’s plenty of doctors who are. If that’s the case, it might be time to consider finding another practitioner that’s willing to work with you to get you what you need.

In my protocol for this week, you’ll find a list of functional lab tests I strongly recommend asking your doctor for at your next visit. These are routine Functional Medicine lab tests that are used to get some concrete answers on what’s going on beneath the surface at every level of your health. If you don’t have anything in particular you’re concerned about, great! Asking for these tests is just another way to solidify that everything is functioning properly.

The Protocol

I. Get the lab tests you need. Here I have laid out what tests to ask for according to each biological system in addition to certain nutrients that are important for the overall function of each system.

The optimal reference ranges provided are taken from my business partner, Dr. Hyman. These are the ranges he uses in his clinical practice, The UltraWellness Center, and are based on years of clinical experience, the clinical experience of doctors that are part of the Institute for Functional Medicine, and the latest research on health and longevity.

These tests and ranges are meant to be a guide. Compare your results to the normal reference range vs. optimal reference range so you can see the difference. A number might be considered “in range” and normal when looking at conventional reference ranges, but out of range when looking at optimal reference ranges.

These lab tests are difficult to interpret if you’re not a trained practitioner because of the natural complexity and interdependent relationship between biological systems. It’s important to make sure you have a skilled practitioner that’s willing to work with you to explain your results and answer any questions you might have.

These tests are available through conventional commercial labs such as Quest Diagnostics or LabCorp.

Please note: lab reference ranges vary depending on where you’re from (reference intervals and units of measure in the US might look different from other countries). They also differ from clinic to clinic and commercial lab companies used for testing.

Disclaimer: The breakdown of these recommended tests is being shared for information purposes only and is not meant to be medical advice. Always make sure to check with your doctor before making any changes to your health routine.

1. Cardiovascular Labs


What it means



LDL cholesterol

The “bad” cholesterol, atherogenic at high levels. Not the best marker for heart disease.

< 100 mg/dL

< 100 mg/dL

HDL cholesterol

The “good” cholesterol, protective against heart disease.

40-50 mg/dL

40-50 mg/dL

> 50

> 60 mg/dL


The storage form of fat, high levels associated with insulin resistance.

< 150 mg/dL

< 150 mg/dL

Triglycerides to HDL ratio

Indicates an elevated risk for heart attack and stroke.

Not available

< 4.0

Total cholesterol

Total cholesterol (LDL + HDL)

200-239 mg/dL

< 200 mg/dL

Total cholesterol to HDL ratio

Indicates an elevated risk for heart attack and stroke.

Not available

< 3.0

Lipoprotein A

A particle of LDL with an Apo(a) particle attached, associated with clogged arteries

< 75

< 30-50 nmol/L

NMR Lipid Testing

LDL particle number: Tells the number of LDL particles present in the blood, a risk factor for heart disease.

1138-1409 nmol/L

< 1020 nmol/L

Small dense LDL particles: The most atherogenic subtype of LDL likely to leave fatty deposits in the blood.

Not available

< 501 nmol/L

VLDL: contains the most triglycerides. A type of bad cholesterol responsible for plaque build-up.

0.1-1.7 mmol/L

< 0.1 mmol/L

HDL size: the larger the size of the HDL particle, the better. An inverse relationship is present between HDL size and heart disease risk.

7.3-8.2 nm/L

Medium: 8.3-9.3 nm/L

9.4-14.0 nm/L

> 9 nm/L

Bonus: ApoB

Since we published this newsletter in 2021, there has been a lot more dialogue and awareness about the biomarker ApoB.

Measuring ApoB tells us the number of disease-causing cholesterol particles in your bloodstream, making it one of, if not the most important, biomarker for assessing heart disease risk.

We’re adding this as a bonus test as more individuals are discussing it as a more accurate measure of heart disease risk than other tests, including LDL.

Different groups have reached different conclusions about optimal ApoB levels, and it seems to depend on other risk factors and comorbidities. In general, the lower your ApoB, the better.

According to this Levels blog, those with type 2 diabetes, heart disease, or obesity should aim for < 80 mg/dL. Healthy individuals should aim for < 100 mg/dL.

For more information, see our further listening below for a deep dive with Dr. Peter Attia and Dr. Andrew Huberman, and my cardiologist, Dr. Michael Twynam.

2. Blood Sugar Labs


What it means



Fasting blood sugar

A snapshot of your blood sugar in time. Not the best measurement of metabolic disease.

65-99 mg/dL

<80 mg/dL


Average blood sugar over the past 3 months. Better indicator of metabolic health.

4.8% – 5.6%

4.8% – 5.5%

Fasting insulin

A better indicator of someone’s risk for diabetes than fasting blood sugar b/c insulin is first to become elevated.

2.6-24.9 µIU/mL

< 5 µIU/mL

3. Immune/Inflammation Labs


What it means




General inflammation. Low-grade inflammation is a sign of chronic disease.

0.0-4.9 mg/L

< 0.7


General inflammation, B12, folate status, and insight on methylation abilities (important for detox).

0-15 µmol/L

< 8  µmol/L

White Blood Cell Count

Low levels can be an early sign of autoimmunity or infection.

4.5-11 x 103/µL

5.0-11 x 103/µL


A clotting factor that increases with inflammation and insulin resistance.

438-517 mg/dL

126-437 mg/dL

4. Liver Function Labs


What it means



Aspartate aminotransferase (AST)

Tests liver enzyme function to indicate if damage is occurring.

5-40 IU/L

< 41 IU/L

Alanine aminotransferase (ALT)

Tests liver enzyme function to indicate if damage is occurring.

7-56 IU/L

< 42 IU/L

Gamma-glutamyl transpeptidase (GGT)

Tests for toxin exposure and fatty liver.

9-48 U/L


5. Kidney Function Labs


What it means




Measures protein in the urine.

< 30 mg/dL

< 20 mg/dL


Urea nitrogen from protein metabolism.

6 to 24 mg/dL

< 20 mg/dL


Waste product that comes from muscle activity that’s removed from the blood and excreted by kidneys.

< 1.3 mg/dL

< 1.2 mg/dL

6. Nutrient Labs


What it means



Methylmalonic acid

Marker for B12 status, critical in gene expression, methylation, nerve function, mood, energy, and more.

0-378 nmol/L

< 300 nmol/L


The storage form of iron. Menstruating women can be low. High levels can be a sign of inflammation or a genetic disorder called hemochromatosis.

30-400 mcg/mL

Women: 15-150 mcg/mL

100-300 mcg/mL

Women: 50-150 mcg/mL

Red Blood Cell Magnesium

Required for over 600 processes in the body, essential for energy production and vitamin D activation.

1.5-2.5 mEq/L

2.0-2.5 mEq/L

Vitamin D

Regulates bone density, supports the immune system, mood, and overall health.

30-100 ng/mL

50-80 ng/mL

Coenzyme Q10 (CoQ10)

Essential for mitochondrial function, heart health, usually low in people taking statins.

0.37-2.20 µg/mL

0.37-2.20 µg/mL

Omega-3 Index

Integral to brain, heart, skin, and hormonal health. Low levels are a sign of inflammation and increased chronic disease risk.

2.9% – 12.9%

8% – 12.9%


Important for making thyroid hormone. A urine test.

34-523 mcg/L

100-300 mcg/L

Red Blood Cell Selenium

Antioxidant activation and use in the body.

120-300 mcg/L

255-300 mcg/L

Red Blood Cell


Important for immune and skin health.

9.0-14.7 mg/L

13.0-14.7 mg/L

Vitamin A

Gene expression, immunity, cell sensitivity, regulates thyroid hormone production and use.

38-98 mcg/dL

68-98 mcg/dL

7. Hormone Labs for Men and Women: 

Please note: If possible, pre-menopausal women’s hormones are best measured on days 19-21 of their menstrual cycle (the luteal phase: when progesterone is at its peak and estrogen is high), where day 1 = first day of a woman’s period. 


What it means




Men: main hormone for brain and heart health, motivation, energy, libido, and sperm health.


> 600 ng/dL

Women: energy, motivation, libido.

20-49 years:

48+ years:

20-40 ng/dL

Free Testosterone

Men: The amount of testosterone that’s not bound to SHBG and able to produce its effect on the body.

20-50 years:

50+ years:

>15-25 pg/mL

Women: same as above.



Sex Hormone Binding Globulin (SHBG)

Men: Binds to testosterone, making it unusable.

20-49 years:
16.5-55.9 nmol/L

49+ years:
19.3 – 76.4 nmol/L

Same as normal

Women: same as above.

20-49 years:
24.6-122.0 nmol/L

49+ years:
17.3-125.0 nmol/L

Same as normal


Men: A precursor of testosterone and estrogen. Dry eyes, dry skin, low sex drive, hair thinning, muscle wasting indicate low levels.


200-450 µg/dL

Women: same as above. Levels decline in mid-20s and are lower with advanced age.

Up to mid-20s:

Up to mid-20s:
150-250 µg/dL

Estrogen (estradiol)

Men: maintain balanced hormones, libido, and a happy brain. Too much can cause “man boobs.”


20-40 pg/mL

Women: healthy mood, energy levels, libido, strengthens bones, protects against osteoporosis.

43.8-211.0 pg/mL

< 6.0-54.7 pg/mL

80-200 pg/mL


Women: calming (reduces anxiety), prepares the uterus for pregnancy.


15-33 ng/dL

Luteinizing hormone

Men: causes testosterone production.


Same as normal

Women: stimulates the release of an egg.



Same as normal

Follicle stimulating hormone

Men: responsible for sperm production.

1.5-12.4 mIU/mL

Same as normal

Women: responsible for ovulation.


25.8-134.8 mIU/mL

Same as normal

LH/FSH Ratio

Women: tells about ovulation and fertility.

Not available

Day 3 of cycle:

8. Thyroid/Adrenal Labs:


What it means



Thyroid stimulating hormone (TSH)

Most commonly run test to check for thyroid disease. Not the most accurate way to test thyroid disorders.

0.45-4.5 µIU/mL

0.5-2.0 µIU/mL

Free T3 (fT3)

The active thyroid hormone. Responsible for energy production, hormone production, bowel movements, and much more.

2.0-7.0 pmol/L

5.0-7.0 pmol/L

Free T4 (fT4)

Main (inactive) thyroid hormone that must be converted to T3. If T4 is normal but T3 is low, this could indicate a conversion issue.

12.0-22.0 pmol/L

15-23 pmol/L

Thyroid peroxidase antibodies (anti-TPO)

A marker of Hashimoto’s, an autoimmune disorder and most common cause of hypothyroidism.


< 2

Anti-thyroglobulin antibodies (anti-TG)

Another marker of Hashimoto’s.

1-115 IU/mL

< 2

Reverse T3 (rT3)

Acts like a brake to stop T3 production. Instead of T4 converting to T3, it converts to rT3, usually in times of stress.

9.2-24.1 ng/dL


Cortisol Test (saliva)

Cortisol levels are highest in the morning upon waking and gradually teeter out for the rest of the day.

Chronically low or high cortisol levels indicate adrenal fatigue (or burn-out) from stress, exercise, or infection.

3.7-9.5 ng/mL

1.2-3.0 ng/mL

0.6-1.9 ng/mL

0.4-1.0 ng/mL

Same as normal

Cortisol Test (blood)

Same as above. Taken between 6 and 8am.

6-23 mcg/dL

Same as normal

Final Thoughts

We weren’t meant to “get through” life, we were meant to enjoy the experience. We don’t want to miss out on the things we love (playing with grandkids, hiking, riding your bike, gardening) just because our health and physical bodies can’t keep up.

Preventative healthcare means creating a long lifespan with just as long of a healthspan to match. Being aware of optimal reference ranges can help you better understand how your body’s functioning overall and whether or not it’s headed down a path of dysfunction and disease.

By having this information, you might feel empowered to make certain changes to your life (whether it’s changing your diet, lowering stress levels, moving around more, or taking more time out for yourself) to get your numbers where they need to be to feel great and live optimally.

Remember, health looks different on everybody. Reference ranges are not the “end-all-be-all” determinants of one’s health status, even optimal reference ranges. So make sure you take into account how you’re feeling as well. After all, being in touch with your body and how you’re feeling mentally and physically is one of the best insights into how things are functioning beneath the surface.

If you know somebody who isn’t feeling great and could use some help finding answers, feel free to forward them this information and tell them to sign up for Try This!

Like all subjects, there are a lot of nuances. Here is a list of articles and podcasts based on the content above.

Further Reading:

Further Listening:

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