Quick answer: When comparing function health vs your doctor annual labs, the difference is scope: Function Health (and comparable proactive lab memberships like Superpower) runs 100 or more biomarkers per draw, while a typical primary-care annual physical orders 6 to 15, nearly all focused on acute disease rather than early warning signals. Neither replaces the other. Your doctor interprets context, orders imaging, adjusts medications, and manages diagnoses. A proactive lab membership finds the slow-moving problems your annual physical is structurally designed to miss. The gap between them is not about quality of care but about what each system is built to do.
What Does a Standard Annual Physical Actually Test?
Most primary-care annuals order a basic metabolic panel (BMP) or comprehensive metabolic panel (CMP), a complete blood count (CBC), a lipid panel, and sometimes TSH. That is roughly 20 to 30 individual lab values, but they cluster around a handful of clinical questions: are your kidneys and liver functioning, is your blood glucose acutely dangerous, are you anemic, and is your LDL high enough to start a statin conversation?
Under Medicare’s Annual Wellness Visit guidelines, preventive labs are tightly scoped because the reimbursement model pays for time and procedures, not comprehensive biomarker surveillance. A PCP who spends 20 minutes with you has to triage, and triage means ordering only what has an immediate treatment implication at that visit. Ordering a DHEA-S, an Lp(a), or a full thyroid panel when nothing is obviously wrong is hard to justify to a payer, even if the result would genuinely change your 10-year trajectory.
Here is what a typical annual physical does and does not cover:
| Category | Usually ordered at annual physical | Usually NOT ordered unless symptomatic |
|---|---|---|
| Metabolic | Glucose, BUN, creatinine, eGFR, electrolytes, liver enzymes | Insulin, HOMA-IR, uric acid, homocysteine |
| Lipids | Total cholesterol, LDL, HDL, triglycerides | ApoB, Lp(a), oxidized LDL, sdLDL particle size |
| Thyroid | TSH only (some PCPs skip it entirely) | Free T3, Free T4, reverse T3, TPO antibodies |
| Hormones | Rarely, unless patient asks or symptoms present | Total testosterone, free testosterone, estradiol, DHEA-S, cortisol, SHBG |
| Inflammation | Sometimes hs-CRP (varies by practice) | IL-6, fibrinogen, ferritin as inflammation marker |
| Micronutrients | Rarely, unless diet concern flagged | Vitamin D (25-OH), B12, folate, magnesium, zinc, iron panel |
| Cardiovascular risk | Standard lipid panel | ApoB, Lp(a), hs-CRP, NT-proBNP |
Notice what is missing: the markers cardiologists and longevity physicians consider most predictive of long-term cardiovascular risk (ApoB, Lp(a)), the insulin resistance markers that predate a diabetes diagnosis by 10 or more years, and virtually every hormone and micronutrient outside a flagged symptom. None of that is malpractice. It is the rational behavior of a clinician operating inside an insurance-reimbursement model that rewards reactive care over surveillance.
What Does Function Health or a 100-Plus Biomarker Panel Actually Run?
Function Health orders roughly 100 biomarkers per draw, grouped into categories that a standard physical simply does not touch: full thyroid cascade (TSH, free T3, free T4, reverse T3, TPO antibodies), comprehensive hormone profiles (testosterone, estradiol, DHEA-S, SHBG, IGF-1), advanced cardiovascular markers (ApoB, Lp(a), hs-CRP, homocysteine), metabolic depth (fasting insulin, HOMA-IR, uric acid), a full micronutrient screen, heavy metals in some panels, and cancer-adjacent markers like PSA, AFP, and CA-125. You draw twice a year and track trends over time.
The operational model is direct-to-lab: you order online, go to a Quest or Labcorp draw site (no PCP referral needed), and results arrive in your online portal with reference ranges and explanatory text. A physician reviews abnormal results before they reach you, though the depth of that review varies by service. For a side-by-side look at how Function Health actually works day to day, including what the portal feels like and where the service has friction, that review covers it in detail.
Comparable memberships like Superpower run a similar biomarker count and pair each result set with a physician review call, which is meaningfully different from automated flagging. The superpower blood test review breaks down exactly which biomarkers are included and how the review process works.
Why Doctors Do Not Test All Biomarkers at Your Annual Physical
The most common misread of this situation is that PCPs are withholding information or being lazy. The structural reality is more mundane: insurance will not pay for it, and without a diagnostic code attached to a symptom or risk factor, ordering a 100-marker panel at a routine visit triggers a billing nightmare. Even a straightforward vitamin D test costs $30 to $90 if ordered without a qualifying diagnosis code, and that charge falls back to the patient after an insurer denies the claim. Most patients do not want surprise bills from their annual physical.
There is also the question of what to do with results. A PCP who orders a full testosterone panel on a 40-year-old man with no specific complaints and finds a low-normal result faces a clinical gray zone: refer to endocrinology (6-month wait), prescribe TRT (off-label territory with liability implications), or advise lifestyle changes (evidence-based but frustrating for the patient). The path of least resistance is not ordering the test in the first place. This is not cynicism, it is a rational response to a system that does not support nuanced surveillance medicine at scale.
Direct-to-consumer lab memberships sidestep this entirely. Because you are paying out of pocket (or with HSA/FSA dollars), there is no insurer to pre-authorize, no diagnostic code required, and no downstream liability for the ordering physician to weigh. You own the data, and you can bring it to any clinician you choose.
The Biomarkers Most Likely to Change Your Trajectory (That a PCP Rarely Orders)
If you are going to argue for getting more labs, these are the markers worth prioritizing, based on what practicing cardiologists, endocrinologists, and metabolic physicians point to most consistently:
- ApoB: A direct count of atherogenic lipoprotein particles. LDL-C can be normal while ApoB is elevated, especially in people with metabolic syndrome or high triglycerides. A 2022 analysis in the European Heart Journal found ApoB more predictive of cardiovascular events than LDL in a broad population sample. Most insurance plans do not cover it without a prior statin therapy failure documented.
- Lp(a): Genetically determined lipoprotein that roughly 20% of the US population carries at high levels. A single lifetime measurement is enough because it barely changes. No lifestyle intervention lowers it significantly, but knowing you carry it justifies stricter LDL targets, aspirin discussions, and earlier imaging. Most PCPs never order it.
- Fasting insulin: Glucose alone misses insulin resistance for years. A person can have normal fasting glucose and HbA1c while running fasting insulin of 20 to 25 uIU/mL, a level that predicts metabolic dysfunction a decade before a diabetes diagnosis. This is one of the clearest cases where direct-to-consumer labs catch something routine care misses by design.
- Free T3 and reverse T3: TSH tells you if the pituitary thinks the thyroid is doing its job. Free T3 tells you what the cells are actually getting. Reverse T3 tells you if stress or chronic illness is shunting active thyroid hormone into an inactive form. People with classic hypothyroid symptoms and a normal TSH often have the answers here.
- Vitamin D (25-OH): The majority of US adults who work indoors are below 40 ng/mL, the level most researchers associate with optimal immune and bone function. Supplementation is cheap. Not knowing costs nothing until it costs you a fracture or a flagged immune panel.
- DHEA-S: Peaks in your mid-20s and declines steadily. Tracking the trajectory tells you more than a single number. Rarely ordered in primary care unless an adrenal condition is suspected.
None of these require a specialist. They require a lab order. That is the gap direct-to-consumer panels fill.
Should You Order Your Own Blood Tests Instead of Seeing a Doctor?
No, and framing it as an either-or choice misunderstands what each does well. Your primary-care physician manages diagnoses, prescribes medications, orders imaging, interprets results in the context of your full medical history, and coordinates specialist referrals. A lab panel, however comprehensive, cannot do any of that. What it can do is walk into that appointment armed with data your doctor did not have and would not have ordered.
The productive model looks like this: run a proactive panel twice a year, review the results yourself first, bring the 3 to 5 findings that surprise you to your PCP or a relevant specialist, and let that drive deeper investigation when warranted. A low-normal testosterone result from a Function Health draw becomes the clinical entry point for a proper endocrinology conversation. An Lp(a) result of 180 nmol/L turns a routine lipid conversation into a specific cardiovascular risk management plan. Your doctor cannot act on data they do not have. You getting that data is a feature, not a circumvention.
The one real caution: direct-to-consumer labs create anxiety in people who are not prepared to handle out-of-range results without clinical context. If you are prone to health anxiety, getting 100 lab values at once, many of which will be slightly outside standard reference ranges simply because those ranges are population-wide averages not optimized for individuals, can be more distressing than informative. Have a plan for what you will do with results before you order. Talk to a clinician about anything that concerns you.
The simplest way to actually get this done
Superpower is a full-body lab membership that runs 100+ biomarkers, has each result reviewed by a doctor, and tracks your numbers year over year (about $199/year). It is what we point readers to when they would rather get one clean, complete draw than chase single tests one at a time. Here is superpower blood test reviewed in full.
Doctor-Ordered Labs vs Function Health: How the Process Compares
Beyond what gets tested, the operational experience of doctor-ordered labs and a direct-to-consumer membership are genuinely different in ways that matter for follow-through:
| Factor | PCP-ordered annual labs | Function Health / proactive membership |
|---|---|---|
| Biomarker count | Typically 15 to 30 values | 100 or more per draw |
| Frequency | Once a year if you book | Twice a year (some services allow more) |
| Insurance coverage | Usually covered for basic panels | Out of pocket, HSA/FSA eligible |
| Annual cost (estimate) | $0 to $200 copays depending on plan | $99 to $499 depending on service |
| Trend tracking | Scattered across multiple EHR portals | Centralized dashboard with year-over-year charts |
| Result interpretation | PCP reviews in context of your full history | Automated explanations plus physician review (varies) |
| Draw site access | Wherever your insurer sends you | Quest or Labcorp, walk-in or appointment |
| Can lead to Rx or imaging | Yes, directly | No, you need a separate clinical visit for that |
The cost comparison deserves a realistic worked example. A 38-year-old with a $1,500 annual deductible and standard Blue Cross coverage gets a standard annual physical with basic labs. If the basic labs are covered as preventive, she pays $0 for the draw. She also wants Lp(a), ApoB, and a hormone panel. Those get ordered separately as diagnostic codes, her insurer denies two of them, and she gets a $180 bill three weeks later for the denied tests, plus a $40 copay for the visit. Total: $220 for 30 biomarkers. A $199 annual membership gets her 100-plus biomarkers, two draws, and trend tracking. The math is closer than people expect, and the coverage is not comparable.
Proactive vs Reactive Blood Testing: Which Approach Finds More
Reactive testing, which is what standard primary care delivers, is designed to catch disease once it has produced symptoms or crossed a clinical threshold. That is the right model for acute illness. It is a poor model for chronic disease, where the useful window for intervention is the 5 to 15 years before the diagnostic threshold is crossed.
Consider the trajectory of type 2 diabetes. The clinical diagnosis happens when fasting glucose exceeds 126 mg/dL or HbA1c reaches 6.5%. But insulin resistance, which is the upstream driver, begins producing measurable signals when fasting insulin starts climbing above 10 to 12 uIU/mL, years before glucose budges. A reactive system that only tests glucose misses the entire preventable window. A proactive panel that includes fasting insulin catches it early, when dietary and lifestyle interventions can fully reverse the trajectory without medication.
The same principle applies to thyroid function, testosterone decline, Lp(a)-driven cardiovascular risk, and vitamin D insufficiency. None of these produce obvious symptoms until the deficiency or dysfunction is severe. By then, you are managing a problem rather than preventing one. The proactive model is not about being a hypochondriac, it is about catching slow signals while you still have leverage.
Where reactive care wins: infections, injuries, acute organ dysfunction, medication management, and anything that has already declared itself as a problem. Your PCP is the right resource for all of that. The goal is to use both systems for what each does best, not to pick one over the other.
For a head-to-head comparison of two proactive lab memberships with different strengths, the function health vs 10x health breakdown covers the biomarker and service differences in detail. And if you are specifically weighing cost, the function health cost page breaks down what each tier actually includes and how it compares to building the same panel yourself at Quest.
Who Gets the Most Value from DIY Labs vs Primary Care Combination
Not everyone needs a 100-biomarker panel. The people who get the highest return on it tend to share a few characteristics. If you are 35 or older and doing everything "right" (exercising, sleeping, not smoking) but still feel suboptimal, a comprehensive panel often reveals the specific deficiency or imbalance driving that. If you have a family history of cardiovascular disease or diabetes, the markers your PCP skips (ApoB, Lp(a), fasting insulin) are exactly the early warning systems you need running. If you are considering starting or adjusting hormones, a baseline hormone panel before you begin is standard of care in functional medicine and nearly impossible to get through insurance without a documented diagnosis.
People who are already well-managed by a specialist (an endocrinologist monitoring thyroid, a cardiologist tracking lipids post-stent) may get less marginal value from a consumer panel because their specialist is already running the relevant markers. The exception is the biomarkers no specialist is tracking because no single specialty owns them, which is most of the micronutrient and comprehensive hormone space.
The Medicare patient deserves a specific note: the Annual Wellness Visit covers a health risk assessment and a personalized prevention plan, but it does not cover the same preventive labs as a regular physical. If you are 65-plus and on Medicare, a direct-to-consumer panel is one of the cleaner ways to get comprehensive labs without navigating Medicare coverage rules, since you are paying out of pocket. HSA accounts roll over from your working years and can be used for this purpose.
If you are also comparing Superpower to Function Health head-to-head for the full panel, the function health vs empirical health comparison covers the physician review model differences, which is where the services diverge most sharply in practice.
FAQ
Is Function Health a replacement for my primary care doctor?
No. Function Health and similar services are lab panels, not clinical care. They cannot diagnose conditions, prescribe medications, order imaging, or manage ongoing health problems. Think of them as a surveillance layer that feeds data into your existing clinical relationships. A result from a consumer panel that concerns you should go to a qualified clinician for interpretation and follow-up.
What blood tests does an annual physical typically include?
A standard primary-care annual typically includes a complete blood count (CBC), a comprehensive or basic metabolic panel (CMP or BMP), a fasting lipid panel (total cholesterol, LDL, HDL, triglycerides), and sometimes TSH and HbA1c depending on age and risk factors. That covers roughly 20 to 30 individual values. Advanced cardiovascular markers, hormones, micronutrients, and insulin resistance markers are rarely included unless you specifically request them and your insurer covers them.
Can I use HSA or FSA money to pay for Function Health or Superpower?
Yes. Direct-to-consumer lab memberships are generally HSA/FSA-eligible as diagnostic lab services. Confirm with your specific plan administrator, since HSA/FSA rules have nuances around preventive vs. diagnostic classification, but most major providers accept these charges without issue. Using pre-tax dollars effectively discounts the membership by your marginal tax rate.
Why do doctors not test Lp(a) at a routine physical?
Lp(a) is not part of standard lipid panel CPT codes, and most insurers will not cover it without a documented cardiovascular event or family history of premature heart disease. A PCP ordering it routinely faces a high denial rate and patient billing confusion. The test itself costs $20 to $60 at Quest, which makes it one of the more straightforward add-ons if you order it directly. It is worth knowing once because it barely changes throughout life, and a high result (above 125 nmol/L or 50 mg/dL, depending on the assay) materially changes cardiovascular risk management.
Will my doctor take results from Function Health seriously?
Results from CLIA-certified labs (Quest and Labcorp draw sites used by Function Health and Superpower qualify) are medically valid. A thoughtful PCP will engage with them. What you should not expect is your doctor to spend 20 minutes walking through 100 results in a 15-minute appointment. The more productive approach: identify the 3 to 5 results that surprised you or fall outside range, bring those specifically, and ask for clinical context or a specialist referral if warranted.
How often should I run a proactive lab panel alongside my annual physical?
Most proactive lab memberships structure draws twice a year, which is a sensible default for catching trends. An annual physical once a year plus two comprehensive draws per year is the typical pattern for someone who is actively optimizing. If you have a specific condition under active management (thyroid, hormones, metabolic), more frequent targeted testing through a specialist makes more sense than another full panel.
Is proactive blood testing covered by insurance at all?
Occasionally. Some insurers cover a broader preventive panel for members over 40 or with documented risk factors, but it varies widely by plan and year. The more consistent path for comprehensive coverage is to have a specific clinical complaint or risk factor documented at your physical, which converts some tests from preventive (often excluded) to diagnostic (often covered). Out-of-pocket memberships like Superpower sidestep this entirely. For a full breakdown of how much superpower costs versus building the same panel through insurance, that page has the math done for several scenarios.
What is the biggest mistake people make when comparing doctor labs to DIY panels?
Treating them as competing products rather than complementary tools. The people who get the most value from comprehensive consumer panels are the ones who bring the data back to their clinical relationships and use it to drive more specific conversations. The people who get the least value are those who use it to avoid the healthcare system entirely, dismissing their PCP, or alternatively, those who treat every slightly out-of-range value as a crisis requiring immediate specialist visits. The panel is a data source. What you do with the data determines whether it helps.
