Common longevity terms

Every LDL, VLDL and Lp(a) particle in the blood carries exactly one ApoB molecule on its surface, so measuring ApoB directly counts the number of potentially artery-clogging particles circulating — regardless of how much cholesterol each one happens to be carrying. Many researchers and clinicians consider this a more accurate cardiovascular risk marker than standard LDL cholesterol alone, since two people with identical LDL cholesterol can have very different particle counts.

→ Whether ApoB is in a provider's standard panel varies, and our comparison page doesn't list markers one by one, so check the provider's own marker list. US blood-test providers are on the comparison page.

Lp(a) is an independent cardiovascular risk factor that's largely inherited rather than influenced by what you eat or how you exercise. Because it's genetically fixed, it typically only needs to be checked once in a lifetime rather than tracked repeatedly like a lipid panel. It's tested alongside — not instead of — standard cholesterol markers, since it captures a different, largely non-modifiable piece of risk.

→ Whether Lp(a) is in a provider's standard panel varies, and our comparison page doesn't list markers one by one, so check the provider's own marker list. US blood-test providers are on the comparison page.

C-reactive protein rises in response to inflammation anywhere in the body. The "high-sensitivity" version of the test can detect much lower, chronic levels of inflammation than the standard CRP test used to check for acute infection — the kind of low-grade, ongoing inflammation that longevity-focused research links to cardiovascular and metabolic disease risk over time, rather than any single illness.

→ Whether hs-CRP is in a provider's standard panel varies, and our comparison page doesn't list markers one by one, so check the provider's own marker list. US blood-test providers are on the comparison page.

Glucose in the bloodstream attaches to hemoglobin inside red blood cells, and red blood cells live for about three months — so measuring what proportion of hemoglobin has glucose attached gives a running average of blood sugar exposure, rather than a single day's snapshot the way a standard glucose test does. It's the standard marker used to track metabolic health and diabetes risk over time.

→ Whether HbA1c is in a provider's standard panel varies, and our comparison page doesn't list markers one by one, so check the provider's own marker list. US blood-test providers are on the comparison page.

A lipid panel is the foundational cardiovascular screening test and a standard part of most general blood panels. It measures total cholesterol along with its main components — LDL ("bad" cholesterol), HDL ("good" cholesterol) and triglycerides (a type of fat circulating in the blood). It's usually the baseline that ApoB and Lp(a) sit alongside, rather than a replacement for either.

→ Each blood-test provider lists its own markers; start from the comparison page and check the provider's own marker list.

What's actually included under "hormone panel" varies more between providers than any other marker on this list — some cover a full thyroid + sex hormone + cortisol panel, others a narrower selection. Hormone levels shift naturally with age and are linked in research to energy, body composition, mood and metabolic health, which is why longevity-focused programs track them rather than leaving them to a standard annual check-up.

→ Check each provider's profile on the comparison page for exactly which hormones are included.

Vitamin D is made in the skin from sun exposure and obtained from a small number of foods, then stored in the blood in a form that's straightforward to measure directly. It's one of the most commonly tracked markers in general health testing — deficiency is widespread even in sunny climates — and is linked in research to bone, immune and metabolic health.

→ Whether vitamin D is in a provider's standard panel varies, and our comparison page doesn't list markers one by one, so check the provider's own marker list. US blood-test providers are on the comparison page.

"Iron studies" isn't a single number but a small panel of related tests that together show how much iron the body has stored and how efficiently it's being transported and used. Both deficiency and excess iron are relevant to long-term health, and iron studies are one of the more commonly abnormal results found in routine testing — which is why longevity panels typically include the full set rather than a single iron reading.

→ Whether a full iron-studies set is in a provider's standard panel varies, and our comparison page doesn't list markers one by one, so check the provider's own marker list. US blood-test providers are on the comparison page.

Originally developed to measure bone density (still the clinical gold-standard for that), a DEXA scan also gives a detailed body-composition breakdown — how much of your weight is fat versus lean muscle, and how it's distributed, including visceral fat around the organs that a bathroom scale or BMI can't distinguish. It uses a very low dose of X-ray radiation and typically takes under 15 minutes. None of the DEXA providers on our comparison page say you need to bring an order from your own doctor (checked Oct 9, 2026).

Not every "DEXA scan" on offer includes the full body-composition breakdown — see BMD scan below for the narrower, bone-only version of the same technology.

→ On the comparison page, BodySpec ($59.95) and DexaFit (from $90, varies by location) offer standalone DEXA scans, and Biograph's program includes one. Checked Oct 9, 2026.

A BMD scan uses the same DEXA (dual-energy X-ray absorptiometry) technology as a body-composition scan, but with a narrower focus: it measures bone mineral density at the hip and lumbar spine specifically, producing a T-score (compared against a healthy young adult) and a Z-score (compared against your own age group) — the standard measurements used to screen for osteoporosis and fracture risk.

This is a genuinely different service to the whole-body DEXA scans marketed for body composition (fat mass, lean muscle, visceral fat) that longevity programs typically offer, even though the underlying machine is the same. A standalone BMD scan is narrower and often cheaper, and when a clinician orders it as part of regular care, the patient's own insurance rules apply (a question for the insurer). Most tests on this site are self-pay. If you want the fuller fat/muscle breakdown rather than just bone density, check directly whether a provider's "DEXA scan" includes body composition or is BMD-only — the two get marketed under the same name more often than they should.

→ Check each provider's listing on the comparison page for exactly what their scan measures.

A whole-body MRI uses magnetic fields rather than radiation to produce detailed structural images across the body in a single session, rather than imaging one specific area the way a typical diagnostic MRI does. It's usually self-pay, and booking rules vary by provider, so check each provider's own listing rather than assuming.

→ On the comparison page, Ezra's Annual MRI is $999 and Prenuvo's Whole Body scan is $2,499, and Biograph and Human Longevity include MRI in their programs. Checked Oct 9, 2026.

VO2 max measures how efficiently your body takes in and uses oxygen when exercising at maximum effort, expressed in milliliters of oxygen per kilogram of body weight per minute (mL/kg/min). It's measured most accurately in a lab via a graded treadmill or bike test with a metabolic cart analyzing your breath, though many wearables (smartwatches, rings) also give an estimated VO2 max from heart-rate and pace data during regular exercise — a convenient estimate, not a lab-grade measurement, and the two can disagree.

→ See our research page for what the evidence actually shows about fitness and mortality risk, and the comparison page for providers that include VO2 max testing (Biograph includes it in its program).

A CAC scan is a low-dose CT scan focused on the heart, looking specifically for calcium deposits in the walls of the coronary arteries — a direct physical marker of atherosclerosis (plaque build-up), rather than an inferred risk factor like a cholesterol number. The result is expressed as an Agatston score: 0 means no detectable calcified plaque, and the score rises with the amount found, with commonly cited bands roughly at 1–99, 100–399 and 400+ used to describe low, moderate and high plaque burden. A score of 0 doesn't rule out all cardiovascular risk (soft, non-calcified plaque isn't picked up by this scan), and it isn't something people re-test frequently — it typically only makes sense to repeat after some years, not months.

It's a distinct test from a standard lipid panel or ApoB blood test — those measure risk factors circulating in the blood, while a CAC scan looks directly at physical plaque that's already there. Some clinicians use blood markers to help decide who might benefit from a CAC scan, rather than treating the two as interchangeable. A CAC scan involves a small dose of ionizing radiation, and whether it needs a clinician's order depends on where it's done, so check the imaging center's own listing.

→ None of the 22 providers on the comparison page lists a standalone CAC scan (checked Oct 10, 2026).

Chemical tags called methylation marks build up on DNA in patterns that shift somewhat predictably with age. A DNA methylation "clock" estimates a biological age from those patterns, which can run ahead of or behind your actual age. This is a fundamentally different test from an ancestry or disease-risk DNA test — it's not looking at your genetic code itself, but at how it's currently being chemically marked. Providers typically frame it as a way to track whether lifestyle changes shift the number over repeated tests, rather than a one-off diagnosis.

GrimAge and PhenoAge aren't separate tests — they're different scoring algorithms ("clocks") that can be run on the same DNA methylation sample. Earlier clocks (like the original Horvath clock) were built to predict chronological age closely; later ones like PhenoAge and GrimAge are instead calibrated against clinical health markers or mortality data, aiming to reflect health risk rather than just count years — which is why the same sample can sometimes produce a different-looking number depending which clock a provider uses. A provider's listing usually names which clock it runs; if it doesn't say, that's worth asking directly rather than assuming.

→ The comparison page lists 4 DNA & epigenetic tests, including mailed kits from TruDiagnostic ($499), Tally Health ($249) and Elysium Index ($299). Checked Oct 9, 2026.

APOE comes in three common variants — e2, e3 and e4. Research has linked the e4 variant to a higher population-level risk of late-onset Alzheimer's disease and cardiovascular disease, though carrying e4 doesn't guarantee developing either condition, and not carrying it doesn't rule them out — genetics is one part of a much larger picture that also includes lifestyle, environment and other risk factors. Because of how sensitive this particular result can feel, some providers offer it as an opt-in add-on rather than a default part of a DNA panel, and genetic counselling is worth considering before or after testing for it.

→ Our comparison page doesn't track which providers include APOE, or whether it's opt-in, so check the provider's own site.

Certain MTHFR variants (commonly labeled C677T and A1298C) are associated with reduced activity of an enzyme involved in folate metabolism and homocysteine regulation. It's a popular inclusion in consumer DNA and longevity panels, but mainstream clinical guidance is more measured than some wellness marketing suggests — major medical bodies generally don't recommend routine MTHFR testing or treatment decisions based on genotype alone, since the link between common variants and real-world health outcomes is weaker and more contested than often portrayed.

→ Our comparison page doesn't track which providers include MTHFR, so check the provider's own site.

In most states, a lab test needs an order from a licensed clinician. Many direct-to-consumer testing companies arrange this through their own physician network, so a customer doesn't need to see their own doctor first. Some states restrict direct-to-consumer testing, which is one reason a test may not be offered everywhere.

→ On the comparison page, "Physician order: Included" means the provider says its own network orders the test. 7 of the 22 providers say so; the rest don't say on the pages we checked (Oct 9, 2026).

Whether a particular test, membership or device counts as an eligible expense depends on the account's rules and the plan, and the plan administrator has the final say. When a company says its product is "HSA/FSA eligible", that's the company's statement, not a ruling. Some companies offer HSA/FSA payment through a third-party service instead. Nothing here is tax advice.

→ 13 of the 22 providers on the comparison page and 10 of the 21 items on the products page say on their own site that they're HSA/FSA eligible (checked Oct 9–10, 2026).

Congress passed CLIA in 1988. The Centers for Medicare & Medicaid Services (CMS) runs the program, which covers laboratory testing on human samples for health assessment or to diagnose, prevent or treat disease. A provider saying its samples go to a CLIA-certified lab is a statement about the lab's quality standards, not about whether a particular test is useful for any one person. CMS: CLIA · checked Oct 10, 2026

→ Where a provider names its lab's accreditation, it's on that provider's card on the comparison page, as the provider's own statement.

A moderate-risk (Class II) device is usually "cleared" through a 510(k), which shows it's substantially equivalent to a device already legally on the market. The highest-risk (Class III) devices generally need FDA "approval" of a premarket approval application. The FDA doesn't approve labs or physician offices, and many consumer wellness gadgets aren't FDA-regulated medical devices at all. FDA: Is it really "FDA approved"? · checked Oct 10, 2026

→ The products page only states a device's FDA status where the brand or the FDA's own database says it, quoted rather than reworded.

Under DSHEA, the FDA doesn't approve dietary supplements for safety and effectiveness before they're sold, and it generally doesn't approve their label claims. Companies are responsible for their products' safety and labeling, and the FDA can act against a product after it reaches the market. Advertising claims fall under the Federal Trade Commission (FTC). FDA: Questions and answers on dietary supplements · FDA: Is it really "FDA approved"? · checked Oct 10, 2026

→ The supplements page covers what DSHEA and the FTC mean for the 4 stacks it compares, and the supplement evidence page sorts common ingredients by strength of evidence.