TSH
Thyroid Stimulating Hormone
LowHigh
Typical healthy reading
Your pituitary's signal to the thyroid. High = thyroid under-responding; low = either plenty of hormone or signal suppressed.
The Science
What your TSH alone can't see.
Four blood markers, seven genetic variants, your symptoms — and the findings engine that pulls them into one story.
The four blood markers
Testly Thyroid measures the same four markers a comprehensive thyroid panel would.
FT3
Free T3
LowHigh
Typical healthy reading
The active form of thyroid hormone — what your tissues actually use. Low Free T3 is a common finding when TSH looks “normal” but you feel fatigued.
FT4
Free T4
LowHigh
Typical healthy reading
The storage form, converted to T3 in peripheral tissues. Conversion efficiency is partly genetic — see DIO1 and DIO2.
Anti-TPO
Anti-TPO antibodies
LowHigh
Typical healthy reading
Autoimmune antibodies targeting thyroid peroxidase. Hallmark of Hashimoto's — the most common cause of underactive thyroid (hypothyroidism).
Plasma — the gold standard
Plasma-based testing is what hospitals and labs use to measure your thyroid markers. Your sample arrives at our lab in liquid form, gets spun down to plasma, and the plasma is tested directly — the same kind of sample you'd get from a blood draw at the doctor's office, just collected at your kitchen table.
Seven genetic variants that shape your thyroid story
A single-nucleotide polymorphism — SNP — is a one-letter variation in your DNA. Most don't matter. A few of them matter a lot for your thyroid. Testly Thyroid looks at seven of them.
The findings engine
From data to findings.
Your report is built around findings — nine specific patterns we look for in your data. Each finding is a story your data tells. Some are well-established and high-confidence. Some are emerging and contextual. Some are reassurance that nothing concerning is showing up. We tell you which is which.
The nine patterns we check for:
- 01The conversion pattern.Trouble making T4 into the active T3 your cells use.
- 02Symptom burden exceeds lab picture.Real symptoms when blood markers look fine — the “you’re not imagining this” finding.
- 03Cellular transport concern.Hormone delivery issues at the cell level.
- 04Early warning pattern.TSH drifting upward; worth catching before it becomes diagnosis.
- 05Individual TSH setpoint mismatch.Your personal range vs. the population range.
- 06Genetic high baseline.PDE8B explains naturally elevated TSH.
- 07Autoimmune evidence.Antibodies present, even before TSH moves.
- 08Underactive-thyroid pattern.Clear “see a doctor soon” signal.
- 09Overactive-thyroid pattern.Same urgency, opposite direction.
Findings are co-authored with our Medical Director and reviewed by a practicing endocrinologist before any of these reach you. Each report includes four to eight findings drawn from these patterns, written in plain language with the science underneath — plus citations to the studies behind every claim.
Standard thyroid reference ranges were built from population averages, not from you.
What we will — and won't — claim
Testly Thyroid is evidence-based. Every finding is grounded in peer-reviewed research. We tell you what's well-established, what's emerging, and what's uncertain.
We don't diagnose. We don't prescribe. We don't replace your physician. We give you a more complete picture so you can make better decisions with the people who do.
Further reading
If you want the source material, we publish the key citations alongside each finding in your report — peer-reviewed papers, with links. We'd rather show you the primary literature than ask you to take our word for it.