Insulin, Free (Bioactive)
The unbound, biologically active fraction of insulin, useful mainly in insulin-treated patients with insulin antibodies.
Consider this test if:
- On insulin therapy with glucose control that does not match your dosing
- Known or suspected anti-insulin antibodies complicating treatment
- Your clinician needs to separate bioactive insulin from antibody-bound insulin
- Investigating unexplained hypoglycemia in an insulin-treated patient
- HSA/FSA eligible
- Results delivered to your dashboard · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
Fasting is generally recommended for insulin measurements. Because this test is used in insulin-treated patients, timing relative to your most recent insulin dose strongly affects the result, so note the dose and time of your last injection. Follow your clinician's instructions on whether to adjust timing around the draw.
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What this test is for
Free insulin measures the unbound, biologically active fraction of insulin circulating in the blood, as opposed to total insulin, which includes insulin bound to antibodies. This distinction matters most in people treated with insulin who have developed anti-insulin antibodies, where total insulin can be misleading and free insulin better reflects what is actually available to lower blood glucose. It is used to make sense of glucose readings and dosing in that specific situation, not as a general screen for insulin resistance.
If your question is metabolic health, insulin resistance, or fasting insulin as part of a blood-sugar workup, the standard Insulin test is the right marker for most people. This free (bioactive) form is the specialized version reserved for insulin-treated patients with confirmed or suspected insulin antibodies, and the separate Insulin Autoantibody test is what identifies those antibodies in the first place.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Fast, dashboard-delivered results
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
Mito Membership
$9 /mo
cancel anytime
Without membership
$0
pay as you go
At-cost pricing on labs, scans, and more
Priority turnaround on your results
On-demand clinician consults when you need guidance
Personalized action plans across supplements, exercise, nutrition, and sleep
AI health coaching to help you act on your results
Year-round medical support, with in-chat clinician escalation
All your health records in one personal vault, with trends and biological age tracking
Early access to new diagnostics and product releases
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost — covering the lab and what it takes to run the service — never a profit on the test itself; Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9/mo, and you still pay the lab’s order fee. Prices are itemized before you pay, with no hidden fees.
Where do I get tested?
Choose a partner lab (Quest, Labcorp, or BioReference) at checkout. If your cart spans multiple tests, we consolidate the whole order onto a single lab so you only make one visit.
Is this eligible for HSA/FSA?
Yes. This test is HSA/FSA eligible, and you can pay with your HSA/FSA card at checkout.
When will I get my results?
Your results post to your dashboard once your lab completes them, then a clinician reviews them and your full analysis and personalized action plan (with clear next steps) follow. Turnaround varies by test: specialty assays and at-home kits take longer, and each test shows its expected turnaround before you buy.
Do I need a doctor’s order?
No. Mito provides the lab order for you, so you can book and get tested without a separate doctor visit.
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