Genuine functional medicine lab tests

Maybe relevant is a better description. Functional medicine lab tests ideally measure things important to our well being or recovery from illness.

The number needed to treat is one measure of relevance. This is how many people would be given an intervention before one of them got a specific benefit. High serum total cholesterol is of little relevance to health if one is in the lowest category of risk with the NNT1 (to prevent one event within 5 years) over 120.

More to the point though, is that cholesterol is not measuring a single function. It is a raw material manufactured in our body for multiple functions.

A better measure of cardiovascular health is testing vascular endothelial function2 as the lining of our blood vessels is where all the action happens.

Essential fatty acids

Mrs H was so thrilled by her recovery she went around teaching other doctors about (her) essential fatty acid tests. She had been close to being bedridden and saw another holistic doc who ordered her functional medicine lab tests including red cell fatty acids...
The first four are shorter and have fewer of the important double bonds. We use the fourth to make the last two (as well as getting these from food.) This woman had above average amounts of all but the last, which was way down because she lacked ability to make it from the others.
Her doctor had given her supplements to enable this synthesis.

If you read about this at the Mayo Clinic site3 they only talk about dietary FA deficiency rather than lack of nutrients needed as cofactors in this biosynthetic pathway.

Mr S was a distinctly unwell 26 year old, irritable, tired all the time, "run down a lot" and would take days to recover from a late night on the computer. He needed more sleep than the average person. He was thirsty all the time.

He also had essential fatty acids measured as part of his workup.

He also, was unable to adequately produce the long chain omega 3 and 6 fatty acids (AA and DHA.) Conventional medicine accepts that the body commonly has a limited capacity in this regard and simply recommends eating more EPA and DHA.


Bill Shive4 of the University of Texas at Austin developed the test5 used by SpectraCell Laboratories, where...
"(Using a) chemically defined, protein-free, medium that would support the growth and proliferation of human lymphocytes... containing only purified substances, including glucose, amino acids, vitamins and minerals—35 cell nutrients in all.

As single nutrients are omitted from the medium, the growth response of the cultured lymphocytes from different individuals differs greatly.

Poor growth implies either low cellular reserves or high biochemical needs, and suggests that the cell donor would benefit from greater dietary or supplemental intake of that nutrient."
The lymphocytes are grown in I understand about 200 media, to check multiple nutrients.

Every cell in our body needs all of the essential nutrients, although in different relative amounts, so this test on transformed lymphocytes is relevant to the whole body to a fair degree.

By comparison, the levels of individual nutrients in any tissue tell very little about how much is needed.


Diagnosis and management of hypothyroidism6 is commonly attempted using just one index, of the body's thyroid accelerator status - the TSH test.

This is fairly insensitive and subject to lots of confounding influences.

What is really of interest is the resting metabolic rate (relative to the environmental temperature.) This is not used as much as it ought to be. The Thyroflex test7 measures the relaxation of a muscle reflex, which is prolonged in hypothyroidism. This correlates better with RMR.


Conventional liver function tests, here in a person with cirrhosis, are very gross indices. This person is unable to make enough albumin protein  and originally came with swollen ankles because of this. They are also unable to make enough clotting factors for their blood, so the tests of these in the lower panel are abnormal. They have difficulty eliminating the waste product bilirubin from their blood, so this is elevated.

More sensitive tests of liver function involve measuring the products of metabolism of a dose of aspirin and paracetamol (acetaminophen.)

Blood glucose after food

Sensitivity or resistance to the action of insulin is usually measured from fasting glucose and insulin levels.9

Much of the damage caused by high sugar levels is due to their increase after we eat, so one of the aims of a good diet is to minimize this spike. Apart from our level of sensitivity to insulin, what we eat has a major effect. Foods have been tested and rated for average glycaemic index10 but there are no average humans.
..."ascribing a single (post prandial glycemic response)PPGR to each food assumes that the response is solely an intrinsic property of the consumed food. However, the few small-scale (n = 23–40) studies that examined interpersonal differences in PPGRs found high variability in the response of different people to the same food (Vega-Lopez et al., 2007; Vrolix and Mensink, 2010.)
This quote is from a study11 in which the researchers were able to predict the individual's glycemic response from "blood parameters, anthropometrics, physical activity, and self- reported lifestyle behaviors, as well as gut microbiota composition and function."

This is genetic testing (here of the gut microbes) coming of age, contributing valuable data. For the most part though, testing one's glucose 2 hours after a meal is the way to see what's best to eat.

Relationships matter, hence ratios

DHEAS and cortisol from our adrenal glands have somewhat opposing actions.

The ratio between them is therefore more indicative of their net effect than the level of either alone.12

References and notes for functional medicine lab tests page.

1. Cardiovascular risk page of this site

2. Endothelial Function Testing as a Biomarker of Vascular Disease.

3. Mayo Medical Laboratories

4. William Shive bio

5. Lymphocyte culture medium test.

6. Thyroid medicine page of this site

7. Trial using Thyroflex test, in which...
" In this population, the evidence supports the hypothesis that physiologic measurements of thyroid function are more accurate at identifying the subclinical hypothyroid state than serum measurements."

8. Health benefits of docosahexaenoic acid (DHA)

9. University of Oxford HOMA calculator

10. University of Sydney home of the glycemic index

11. Personalized Nutrition by Prediction of Glycemic Responses

12. Raised cortisol:DHEAS ratios in the elderly after injury: potential impact upon neutrophil function and immunity.


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DHA is 22 carbon atoms long and 6 double bonds, the last being 3 carbons back from the tail end. It is very important for our brain especially8.

For a good rant on the TSH test see the page on

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