Testing & Diagnostics

At-Home Health Testing Guide: Function Health vs InsideTracker vs Quest (2026)

By Trevor Kaak · Published May 13, 2026 · Last verified May 13, 2026 · ~19 min read
Testing & Diagnostics

I've spent roughly $3,200 of my own money over the last three years getting my blood tested, scanned, sequenced, sampled, and otherwise inspected. Some of it was genuinely useful. Some of it was an expensive way to feel productive about my health while changing nothing.

This guide is the version of that journey I wish someone had handed me in 2023. It walks through what at-home health testing actually is in 2026, who the real players are, what's worth paying for, and — importantly — when you should just put your wallet away and call your primary care doctor instead.

Key Takeaways

Medical disclaimer: I'm not a doctor. Nothing in this article is medical advice, diagnostic guidance, or a substitute for working with a licensed clinician. Blood tests may indicate potential concerns; they don't diagnose anything on their own. If a result alarms you, talk to your physician. Full disclaimer at the bottom.

Why baseline blood work matters (the actual case)

Here's the part of the longevity narrative I think is mostly correct: the median American adult goes years between meaningful blood draws, and the panels their PCP orders during an annual physical are minimal — usually a basic CBC, a CMP, and a standard lipid panel. That's fine for catching dramatic abnormalities. It's not fine for trends, and trends are where most chronic disease lives.

Three things shifted my thinking:

  1. Cardiovascular disease is still the #1 killer in the US, and the cheap, standard "lipid panel" (total cholesterol, LDL-C, HDL, triglycerides) misses a lot. The American Heart Association's recent guidance and a growing body of research point to apolipoprotein B (ApoB) and lipoprotein(a) (Lp(a)) as better risk indicators than LDL-C alone. Most PCPs still don't order them by default.
  2. You only get one Lp(a) test in your life. It's almost entirely genetic. Roughly 1 in 5 people has elevated Lp(a), and most have never been tested for it. (See: Tsimikas et al., JACC 2017.)
  3. Trends beat single data points. A fasting glucose of 94 mg/dL is fine. A fasting glucose of 94 mg/dL after it was 81 last year and 86 the year before is a story.

So: there's a real argument for occasional comprehensive panels. The question is how you get them.

The at-home health testing landscape in 2026

The category has fragmented since 2023. Here's how I now mentally bucket the players.

Direct-to-consumer (DTC) testing platforms

These are the brand-name companies running marketing campaigns on your Instagram feed. They handle the lab order, the draw (usually via a partner like Quest or LabCorp), the dashboard, and — to varying degrees — the interpretation.

Raw lab access (Quest, LabCorp DTC)

The two largest US lab companies both run consumer-facing portals where you can order tests on yourself, walk into one of their draw stations, and get results emailed to you.

You get the same lab data the doctors get, at a significantly lower price. You don't get the interpretation, the dashboard, or the lifestyle recommendations.

Specialized testing

Whole-body imaging and screening

A different beast. These are imaging-based, not blood-based, and the price is in a different universe.

What to test (and why)

If you're going to spend money on blood work, here's the panel I'd actually want, sorted by what I think the priority order should be. This is not medical advice — it's how I'd think about building a panel if I were starting over.

The basics (any panel should include these)

Complete Blood Count (CBC) — Red cells, white cells, platelets. Cheap, ubiquitous, occasionally catches things like anemia, infection, or rare blood disorders.

Comprehensive Metabolic Panel (CMP) — Electrolytes, kidney function (creatinine, BUN), liver enzymes (ALT, AST), glucose. Same deal: cheap, foundational, catches obvious problems.

Standard lipid panel — Total cholesterol, LDL-C, HDL, triglycerides. Useful but limited.

Advanced cardiac (the part most PCPs miss)

This is where DTC testing earns its keep, because most primary care visits don't include these by default.

Metabolic

Hormonal

For men: Total testosterone, free testosterone, SHBG, estradiol (sensitive assay), LH, FSH. Get tested fasting, before 10 AM, after at least one day off the gym.

For women: Hormonal testing is much more context-dependent on cycle, age, and life stage. If you're considering hormone testing, this is where I'd argue strongly for working with an actual endocrinologist or women's-health specialist instead of a DTC dashboard.

For everyone: TSH, free T4, free T3. Thyroid function affects almost everything else.

Cortisol — Tricky. A single morning serum cortisol tells you very little. Salivary cortisol curves (4 samples across a day) are more useful but harder to get.

Inflammatory markers

Vitamins, minerals, micronutrients

Heavy metals (situational)

I tested for lead, mercury, arsenic, and cadmium once after eating a lot of canned tuna in 2022. Results were fine. I would not recommend running heavy metals testing as a routine "longevity" panel — only if you have a specific exposure concern.

The 5 contenders, compared

Here's the head-to-head on the major DTC players, based on panels I've personally ordered (Function Health, InsideTracker, SiPhox, Quest DTC) and one I've ordered for a family member (LabCorp OnDemand).

TestPriceBiomarkersCadenceIncludes draw fee?Result timeMy grade
Function Health$499/yr100+2x/year baseline + add-onsYes (Quest)5–14 daysA-
InsideTracker Ultimate$699 one-time48One-timeYes (LabCorp or home)7–10 daysB+
Quest Health DTC$150–$40030–80 depending on panelDIYLab draw included2–5 daysA (for value)
LabCorp OnDemand$150–$400SimilarDIYLab draw included2–5 daysA-
SiPhox Ultimate$29550Quarterly availableMail-in finger-prick5–7 daysB

Function Health

The current darling of the longevity-coded fitness internet. $499/yr gets you two comprehensive panels — over 100 biomarkers each — plus a dashboard with reference ranges, "optimal" ranges, trend tracking, and an AI-assisted result summary. They also offer occasional add-ons (heavy metals, microbiome, additional hormones) for fees on top.

What's good: The platform is genuinely the best in this space. The panel is comprehensive. The "two panels a year" cadence is enough to start seeing real trends without becoming neurotic.

What's not: The "AI doctor" interpretation is mediocre. The longevity-coded marketing oversells what blood markers can actually tell you about lifespan. And $499/yr is real money.

I have a 14-month, 4-panel review here: Function Health Review.

InsideTracker

The OG of the at-home blood-test space — they've been around since ~2012 and were the first company in this category I tried. Athlete-focused: their recommendation engine is built around training, recovery, and nutrition rather than longevity per se.

What's good: The food/supplement/lifestyle recommendations are unusually actionable. The DNA add-on (one-time genetic baseline integrated into the dashboard) is interesting. UX is solid for first-time blood-test users.

What's not: The "InnerAge" feature is a gimmick — it's computed from a handful of biomarkers and the literal predictive value of "your biological age is 34" is close to zero. Subscription nag for their supplements is annoying. Panel size is smaller than Function Health.

Full review: InsideTracker Review.

Quest Diagnostics DTC (questhealth.com)

The "just order the panel yourself" option. Pick from menu, pay with credit card, walk into a Quest draw station, get results in 2–5 days.

What's good: Cheap. The same panel Function Health uses (they're a Quest partner). You can order exactly what you want.

What's not: No interpretation, no dashboard, no recommendations. You're getting a PDF.

This is what I tell people with high-deductible insurance plans or anyone who already has a doctor willing to look at results: just order it yourself.

LabCorp OnDemand

Quest's main competitor. Essentially the same value proposition. Slightly different test menu. Pick whichever has a draw station closer to you.

SiPhox Health

Different model: they ship you a finger-prick kit, you mail it back, results come back in about a week.

What's good: No venipuncture, no driving to a draw station. Useful if you live somewhere remote.

What's not: Finger-prick panels have inherent limitations — some markers (like Lp(a), ApoB) are well-validated, others are less reliable than venous draw. Panel is more limited than Function Health.

Best for athletes

InsideTracker. The recommendations are built around training adaptation, recovery markers, ferritin/iron status, and the kinds of metabolic markers that actually move with hard training. Add the DNA panel and you get a one-shot performance baseline.

Second pick: Marek Health if you want something more focused on hormones and performance, less on general wellness.

Best for longevity tracking

Function Health. This is where the twice-yearly cadence pays off — you actually get trend data over multiple years. ApoB, Lp(a), hs-CRP, fasting insulin, A1c, full thyroid panel, and the standard vitamin / micronutrient suite are all in the baseline.

That said, no blood panel tells you how long you're going to live. The honest version of the longevity case is: certain markers (ApoB, Lp(a), A1c, hs-CRP, fasting insulin) are good predictors of disease risk, and managing them down likely reduces that risk. That's it. There's no biomarker that tells you "you're going to live to 95."

Best for budget

Quest DTC or LabCorp OnDemand. You can build a personal panel with the most important markers — ApoB, Lp(a), hs-CRP, A1c, fasting insulin, full thyroid, vitamin D, B12 — for under $250. The catch is you have to interpret the results yourself or convince your doctor to look at them. (Most doctors will, if you bring them in and ask politely.)

For the absolute cheapest path to "I know my Lp(a)": order a single Lp(a) test from Quest DTC for about $32. Do it once. You're done forever.

Best for women's health

This is the category where I have the least personal experience and the most caution. Women's hormonal health is more cycle-dependent, more context-dependent, and frankly more poorly served by the DTC dashboards, which often display male reference ranges as the default.

If I were a woman building a testing plan:

Honestly: this is the area where I'd most strongly suggest working with a clinician rather than relying on a DTC dashboard alone.

CGMs as a separate category

Continuous glucose monitors have moved from "you need a prescription and a diabetes diagnosis" to "walk into CVS and buy one" in the span of about 18 months (Stelo got FDA OTC clearance in August 2024).

Whether you should wear one is its own question, with a real evidence vs. hype tension. I cover it in depth in Best CGM for Non-Diabetics (2026).

Short version: a CGM is most useful as a 1–3 month learning tool, not a forever subscription. If you're metabolically healthy, fasting glucose is reliably under 95 mg/dL, and A1c is under 5.4, the CGM is a $90/month curiosity, not a clinical tool.

What I actually do (my testing cadence)

Since you read this far, here's my real personal protocol as of May 2026. This is what I do. It's not what you should do.

Total annual spend on testing: ~$700.

The "longevity" claims: what's real, what's marketing

I want to spend a section on this because the marketing in this category is bad and getting worse.

The honest pitch for any of these services is: here's a comprehensive blood panel, twice a year, in a usable dashboard, with reasonable reference ranges. That's a real product. The "longevity platform" framing is largely marketing.

Reading your own labs: basic literacy

If you're going to order tests, you should be able to read them at a basic level. Here's the absolute minimum.

Reference ranges vs. optimal ranges. Lab "normal" ranges are usually 95% population intervals — meaning ~5% of healthy people fall "out of range." That's why some DTC platforms display narrower "optimal" ranges. Both have their place. Out-of-reference is worth investigating; outside-optimal-but-inside-reference is usually worth watching, not panicking about.

Trends matter more than single values. A single elevated reading on anything could be an artifact (you didn't fast, you were dehydrated, you ran 10 miles yesterday). Repeat before acting.

Lp(a) — One number, mg/dL or nmol/L. Under ~30 mg/dL = lower risk. 30–50 = moderate. Over 50 = elevated. Above 75–100 = high. Genetic and stable.

ApoB — In mg/dL. Most current guidance suggests under 90 for general adults, under 80 for elevated cardiovascular risk, under 60 for established CVD or very high risk. (Talk to your doctor — these targets are debated.)

hs-CRP — Under 1.0 mg/L is low risk, 1–3 is moderate, over 3 is elevated for inflammation. Major caveat: this spikes with acute infection or recent intense exercise. Don't test 48 hours after a marathon.

Fasting insulin — Under 10 μIU/mL is generally considered fine; under 5 is "optimal" by some interpretations. Combined with fasting glucose, you can compute HOMA-IR — a rough insulin-resistance estimate.

Hemoglobin A1c — Under 5.7% = normal. 5.7–6.4% = prediabetes range. Over 6.5% on two separate tests = diabetes diagnostic threshold.

Vitamin D (25-OH) — Under 20 ng/mL = deficient. 20–30 = insufficient. 30–60 = generally considered sufficient. (Optimal range is debated.)

Ferritin — Highly context-dependent. Low (under 30 ng/mL in women, under 50 in men) often indicates iron deficiency. High (over 200) can indicate inflammation or, rarely, hemochromatosis.

Action steps after results

The most common mistake people make after getting comprehensive blood work back: panic on a single elevated marker and either (a) ignore it because it's scary or (b) immediately start ordering supplements based on a forum post.

The right sequence:

  1. Read the report twice, including reference ranges.
  2. Identify the 1–3 markers most out of range or trending wrong.
  3. Bring the results to your actual primary care doctor. Bring printouts. Most PCPs are happy to look at outside labs if you bring them in and ask specific questions.
  4. For anything seriously out of range, ask for a repeat draw to confirm, and ideally for an ICD-coded order that goes through insurance (so future re-tests are covered).
  5. Address the easy stuff first. Vitamin D low? Take vitamin D. Ferritin low? Look at iron intake. A1c creeping up? Look at sleep, alcohol, refined carbs.
  6. Don't chase every marker into a rabbit hole. Some out-of-range readings just are.

YMYL Medical Disclaimer

I am not a physician, nurse, dietitian, or other licensed medical professional. The content on RecoveryStack — including this article — is for informational and educational purposes only.

Blood tests, biomarker panels, CGMs, and other forms of self-testing do not diagnose disease. They may indicate the need for further evaluation by a licensed clinician. They may suggest areas worth investigating. They are not a substitute for the judgment of a physician who knows your full medical history.

If a test result concerns you, contact your primary care provider. If you have symptoms suggestive of a medical emergency, call 911 (US) or your local emergency number.

Affiliate disclosure: RecoveryStack may receive a commission if you purchase through links on this page. This does not affect our editorial judgment. I paid for every product reviewed here out of my own pocket.

FAQ

Venous-draw blood testing through Quest or LabCorp (which is what Function Health and most InsideTracker tests use) is the same lab process your doctor uses. Finger-prick mail-in testing (SiPhox, some at-home kits) is generally accurate for the markers they're validated for, but less so than full venous draws.

For DTC services like Function Health, InsideTracker, Quest DTC, and LabCorp OnDemand — no. They have arrangements with telemedicine physicians who sign the lab orders on the back end. (This is why some tests aren't available in NY, NJ, and RI, where state laws are stricter.)

Almost never. DTC testing is pay-out-of-pocket. The exception: some HSA/FSA accounts will reimburse DTC blood tests as eligible health expenses. Save your receipts.

For ongoing trend-tracking and the most comprehensive baseline: Function Health. For a one-time deep dive with actionable training/nutrition recommendations: InsideTracker. If budget is tight: Quest DTC.

Order it à la carte from Quest DTC or LabCorp OnDemand. Usually under $40.

Probably not, unless you have specific cancer risk factors or strong family history. The evidence on full-body MRI screening for asymptomatic adults is weak, and the false-positive rate produces real anxiety and downstream procedures.

For most healthy adults under 50 with no elevated cancer risk: probably not yet. Sensitivity for early-stage cancers in the most-validated cohorts is still limited. Talk to your oncologist or PCP if you have specific risk factors.

For most adults: a comprehensive panel every 6–12 months is plenty. Twice a year is the natural cadence Function Health is built around and is reasonable. Quarterly is overkill for most people and produces a lot of noise.

For most lipid markers (including ApoB and standard cholesterol), fasting is no longer strictly required — non-fasting lipids are now considered acceptable per AHA guidance. For glucose and insulin, yes — fast 10–12 hours.

Yes, and you should. Function Health, InsideTracker, Quest, and LabCorp all let you download a PDF report. Bring it to your next physical.

For ancestry: sure, if that's interesting to you. For health: limited. They don't sequence — they genotype a fixed panel of variants. They miss most of the rare variants that actually matter clinically. And the 2023–2024 data breach situation hasn't fully resolved as of 2026.

For most people: fasting insulin. It's not on the standard PCP panel, it's cheap, and elevated fasting insulin is one of the earliest signals of metabolic dysfunction — often years before A1c moves.

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About the author

Trevor Kaak writes about recovery, longevity, and performance optimization at RecoveryStack. He's spent over $3,000 of his own money on blood testing, body comp scanning, and diagnostic services since 2023, and writes about which ones were worth it and which weren't. He is not a physician.

TK

About the author

Trevor Kaak founded RecoveryStack after spending six figures on recovery and longevity gear and getting burned enough times to want to save other people the trouble.

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