QUICK TAKES

🔍 Diagnosis vs. Screening: Know the Difference Got symptoms? DIrect-to-Consumer (DTC) tests are usually not the best choice. They're screening tools for healthy people, not diagnostic tools.

🕳️ The Primary Care Vacuum Your regular doctor won't order some tests like fasting insulin because they don't know what to do if it's abnormal. There may be no guidelines. You may be left not knowing what is possible or realistic without access to a physician who has experience working with certain tests.

💸 You're Already Paying Stop letting insurance companies off the hook. You pay premiums—make them cover legitimate testing.

⚖️ Balancing Hormones Traditional docs refuse to prescribe certain hormones sometimes due to outdated fears. DTC companies capitalize with "hormone optimization" marketing. Safe and appropriate targeted treatment gets crushed between medical timidity and commercial greed.

FAVORITE FINDS

You can use your existing tests to calculate your own “biological age.” These inexpensive biomarkers turn out to perform better in research than more complicated epigenetic clocks.
And you can use the rest of Dr. Fitzgerald’s approach to improve your biological age.

Some of my favorite non-DTC testing:

• Boston Heart Diagnostics: they offer a good selection of useful tests, which insurance covers in many cases, and that are well-priced when insurance isn’t available

• Genova NutrEval: it’s on the expensive side, but a really comprehensive test including heavy metals, micronutrient analysis, and oxidative stress testing including glutathione level, lipid peroxides, 8-OHDG, amino acid levels — some biomarkers have more evidence than others but it has been helpful in helping guide patients towards better health

• Vibrant Food Tolerance testing: we are finally getting research support for IgG-based food tolerance testing. This test also may include a celiac panel, and other useful information. I don’t recommend all the tests this lab offers, it’s complicated!

• Professional Co-op is a discount service available to physicians, that uses LabCorp facilities. Also, supplement dispensary Fullscript is now offering discounted Quest lab testing.

Deep Dive

The Promise and Pitfalls of Direct-to-Consumer Testing

The Growing Trend

We’ve had an explosion of companies offering tests directly to consumers, complete with "a clinician visit" for prices ranging from $150 to a lot more. Many people wonder: are we finally seeing the empowerment of patients, or a new way of taking advantage of them? The answer, as with many things in healthcare, is complicated.

There is no question that the profitability of these new ventures relates to not having to take care of people with significant medical needs. People with uncomplicated situations pay monthly or yearly fees for blood testing, plus a prescription in some cases. That is certainly not hard to do profitably.

We also have screening blood testing (such as Grail and Function Health) and screening imaging such as Prenuvo. The problem with cancer screening tests has to do with understanding the statistics of testing. The problem with blood tests resides in not understanding the difference between diagnosis and screening.

The bottom line with some cancer screening is that if the test is positive, there’s still a very good chance you don’t have the problem, and all subsequent further testing or biopsy is usually wasted time, energy, anxiety, and side effects. And if the test is negative, that’s still not 100% and you could be falsely reassured. Tests we have been performing for decades (like mammograms and the PSA) have usually worked out these issues, to a point.

When These Services Can Be Valuable

The Function Health Example

Many people come to see me after getting labs drawn through Function Health. I’ve known Mark Hyman for decades, have learned from him over the years, and respect his approach. Function Health includes some very useful tests that you might not get from a conventional physician.

While it can't possibly include everything important to everyone—and will necessarily include things some people don't need—I don't think it's a bad deal if you:

• Don't currently have a doctor

• Want to screen yourself for more than the basic health markers

• Are uncertain about investing in a functional medicine consultation

• Want your initial functional medicine consultation to be informed by some lab results instead of having to wait until the second visit

The Primary Care Gap

However, here’s the reality: if you have a primary care provider, they probably won't be excited to work with tests like fasting insulin, apolipoprotein B, or free T3. The reason they don't order these isn't stubbornness—it's because they don't have strategies to address abnormal results. It's actually correct medical practice for a physician not to order tests they can't act upon.

And if you already have a functional medicine doctor, DTC testing services are probably overpriced. Some of the tests are covered by insurance, and some can be obtained for low prices if your physician has an interest in finding inexpensive testing sources. Actually I tried to see if I could match Function Health pricing and found that:

• I can’t! They have outstanding bulk pricing. To save people money I rely on insurance coverage for tests conventional medicine normally uses, and/or on tailoring the panel

• The repeat testing is really basic: most things that are wrong with people would require add-on follow up testing

The main thing to understand is the difference between ordering a test because a person has a symptom and you are trying to find the cause (diagnosis), and ordering a test in case a person has a problem they don’t know about (screening).

DTC tests can provide reassurance, or a clue a person might want to go further to find out how they can be healthier. However, they cannot diagnose a person who is complaining of symptoms—for that, you'll need to work with a physician regardless. That’s because diagnosis is in fact harder than it looks: ideally you want a lot of context (a full history) and a fair deal of education and experience.

Red Flags: When Companies Oversell

Misleading Categories

Some companies I see are definitely exaggerating their capabilities. Their websites list lofty categories like "cognition" or "liver function and toxicity," but when you examine the actual tests offered, there's simply no way those tests can answer those questions.

Also, while a licensed professional must sign off on the labs, the person meeting with the client may be someone without a professional license, thus would not be allowed (by law) to diagnose, treat, prescribe, or interpret labs, and could only “discuss results” in a wellness or educational context rather than provide medical advice.

The Bottom Line

I'm not saying everyone needs a fully licensed professional every time they want basic health information. But proceed with caution and don't assume these companies are automatically on your side.

Consider direct-to-consumer testing if:

• You can't access a primary care doctor

• It’s the best option financially

• You want basic screening and understand the limitations

• You're prepared to work with an appropriate physician if anything abnormal turns up

Take it with a grain of salt if:

• The marketing promises seem too good to be true

• You're looking for diagnosis (a reason for a symptom) rather than screening (finding something wrong when there is no symptom)

• The "clinician consultation" seems too brief or inexpensive to provide real medical care

In addition:

• Don’t take the burden off your insurance company — you are already paying through your premiums, so let them pay for what they owe.

• Ask for greater expertise: analyses show that health insurance companies and medical centers are continuing to explode administrative costs and executive compensation. From 2005 to 2015, physician salaries increased only 10% compared to the 93% CEO increase during the same period. They can afford to hire well-trained and credentialed personnel, and treat them well. The crisis in primary care is not a mysterious occurrence. 

It’s bad enough that in our system so many people good insurance, but in addition we are creating a two-tiered system where people with money risk getting overtreated while those without struggle to avoid undertreatment. (As an aside, mea culpa: I spent 20 years of my medical career as a PCP in community health centers, but since I’ve been focusing on functional medicine, I have practiced out-of-pocket medicine that leaves patients with the entire financial responsibility).

The MHT/BHRT Problem: A Perfect Storm

The Medical Establishment's Failures:

Many physicians reflexively refuse menopausal hormone therapy (MHT), or bioidentical hormone replacement therapy (BHRT) for reasons that are sometimes related to:

• Fear of harming patients stemming from outdated interpretations of studies like Women's Health Initiative (WHI)

• Lack of updated training in menopausal hormones

• No clear guidelines on what to do for women with premature menopause

• Dismissive attitudes toward women's symptoms (the "it's just menopause, deal with it" mentality; or worse)

Enter the Opportunists:

Direct-to-consumer companies swoop in with aggressive marketing promising to "optimize" hormones and tests that sometimes aren't clinically meaningful.

Menopausal Hormone Therapy

• Makes sense when a woman’s symptoms coincide with a drop in estradiol (and sometimes with drops in progesterone or testosterone)

• Can be used for as long as there’s no obvious contraindication; there is no need to stop, in the guidelines.

• Women or any humans should not have one aspect of their health treated in isolation from all the others: lifestyle, and the rest of the body, impact well-being whether you are menopausal or not, on MHT or not.

The Broader Pattern

This same dynamic plays out across functional medicine:

• Physicians dismiss certain concerns → Companies sell expensive tests that may not properly inform management

The real tragedy: There's often a legitimate middle ground where targeted testing and treatment would actually help people, but both the conservative medical establishment and the opportunistic DTC companies miss it.

Good medicine gets squeezed out by both medical timidity and commercial exploitation. The patients caught in the middle are the ones who suffer, either from dismissive care or predatory marketing.

And now let’s tackle the real problems:

• burnout in a majority of physicians (60% range) (Dzodzomenyo et al, 2024)

• gaslighting, especially of women (Nelson AJ, 2018)

• appointments that are too short (Bryce, et al. 2022)

• physicians who have major conflicts of interest (Barbeira et al, 2023)

• clinic owners/admin/private equity with major conflicts of interest (Lo and Field, 2009)

• a barrage of dangers in our daily lives, from toxins to unhealthy food (Hailey et al, 2024)

• rising rates of chronic illness and chronic medications (Anderson et al, 2025)

• too many antibiotics, still! (Bhowmik et al, 2023)

• I’m leaving out a bunch, feel free to comment…

REFERENCES

Anderson AJ, Li J, Wang X, et al. Trends in Multiple Chronic Conditions Among US Adults, By Life Stage, 2013–2023. Prev Chronic Dis. 2025

Barberia LG, Silva AA, Pacheco RC, et al. Financial conflicts of interest among US physician authors of 2020 clinical practice guidelines: a cross-sectional study. BMJ Open. 2023

Bhowmik A, Chatterjee I, Saha S. Antimicrobial Resistance: A Growing Serious Threat for Global Public Health. Antibiotics (Basel). 2023

Bryce C, Pereira AG, Jones T, et al. Association between primary care appointment lengths and subsequent healthcare utilization. BMC Primary Care. 2022

Dzodzomenyo M, Vervoort D, Gohil J, et al. Physician Burnout: Evidence-Based Roadmaps to Prioritizing and Mitigating Burnout. Cureus. 2024

Helley MP, Nabi S, Tabassum N. Linking environmental exposure to toxicants and chronic disease. Int J Environ Res Public Health. 2024

Lo B, Field MJ, editors. Conflicts of Interest and Medical Practice. Washington (DC): National Academies Press (US); 2009

Nelson AJ. The toxic power dynamics of gaslighting in medicine. Can Med Assoc J (CMAJ). 2018