Soluble Transferrin Receptor (sTfR)
Detects iron deficiency even when inflammation makes ferritin unreliable.
Consider this test if:
- Anemia alongside an inflammatory condition, chronic infection, or malignancy that makes ferritin hard to interpret
- Symptoms of iron deficiency (fatigue, weakness, poor exercise tolerance) but a normal or elevated ferritin from coexisting inflammation
- Distinguishing iron deficiency anemia from anemia of chronic disease
- Chronic kidney disease, hemolytic conditions, or thalassemia where standard iron markers mislead
- HSA/FSA eligible
- Typical results in 2-3 days · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required. A standard blood draw; gross hemolysis can invalidate the sample. If you take iron supplements, note the dose and timing, since active erythropoiesis influences the result.
Video consult with your Care Team
A 1:1 call to discuss your health.
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What this test is for
Soluble transferrin receptor (sTfR) reflects how hungry your cells are for iron. When iron runs low, cells increase transferrin receptors to pull in more, and a measurable fragment sheds into the blood, so sTfR rises in iron deficiency. Its main advantage is that, unlike ferritin, serum iron, and total iron-binding capacity, it is not appreciably distorted by inflammation, infection, or chronic disease, which makes it the marker of choice for spotting iron deficiency hidden inside anemia of chronic disease. sTfR also tracks the rate of red-cell production, so it climbs with hyperplastic erythropoiesis (hemolytic anemia, beta-thalassemia, polycythemia) and falls when production is suppressed (chronic kidney disease, aplastic anemia, post-transplant). It is most useful paired with ferritin: when ferritin is ambiguous because inflammation is in play, sTfR helps separate true iron deficiency from anemia of chronic disease.
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 Typical results in 2-3 days
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
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Without membership
$0
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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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