A TSH of 3.46
| Where it fallscommonly reported adult reference ranges | Within the reference range |
|---|---|
| TSH | 3.46mIU/L |
| Usual reference range | 0.4 – 4.0mIU/L |
| Suppressed | under 0.1mIU/L |
| Below the reference range | 0.1 – 0.39mIU/L |
| Within the reference rangethis reading | 0.4 – 4mIU/L |
| Mildly raised | 4 – 9.99mIU/L |
| Clearly raised | 10 and abovemIU/L |
Notes
- One reading is not a diagnosis. TSH moves with the hour of day — it peaks overnight and troughs in the late afternoon — as well as illness, pregnancy and several medicines. A clinician reads it against your history and usually against a repeat, not on its own.
- Reference ranges differ between laboratories. The bands above follow commonly reported adult reference ranges. Your own report prints the range its analyser was calibrated against, and that printed range is the one to compare against — a difference of a few units between labs is normal and does not mean either is wrong.
- TSH moves opposite to thyroid hormone. A high TSH is the pituitary pushing a gland that is producing too little, so a raised number points to an underactive thyroid, and a low number to an overactive one. That inversion is the single most common misreading of this result.
- A TSH between 4 and 10 with normal free T4 is subclinical hypothyroidism, and whether it is treated is genuinely contested. Age, symptoms, thyroid antibodies, pregnancy or plans for it, and cholesterol all weigh into that decision. It is one of the few lab results where two competent clinicians reasonably reach different conclusions from the same number.
- TSH swings by the hour and by the season. It peaks overnight and is lowest in the late afternoon, varying within an individual by up to about 40% across a day. A borderline result is usually repeated, ideally at the same time of morning, before it means anything. Biotin supplements — common in hair and nail products — also interfere with the assay and can produce a misleadingly low result.
What tsh of 3.46 mIU/L means
A reading of 3.46 mIU/L falls in Within the reference range by commonly reported adult reference ranges.
The usual reference range is 0.4 – 4.0 mIU/L.
Reading it next to the rest of the picture
A single figure is a snapshot. What a clinician does with it is set by what sits around it — the other results on the same report, what the person is being treated for, what they were doing in the hours before the sample, and what the previous result was. Two people can hand over the same number and leave with different advice, and neither has been given the wrong answer.
That is also why the bands on this page are drawn from a named guideline rather than from a rounded rule of thumb. A threshold is a decision point somebody argued for in print, not a law of nature, and knowing which document a line comes from is what lets you tell a meaningful result from a borderline one.
Nearby sizes
Read more
- CBC Normal Ranges — What Each Line on the Result MeansA value marked high or low on a CBC is common and is often not significant on its own. The pattern across lines is what a clinician reads.
- eGFR Normal Range: Above 90, and the Stages Below IteGFR is an estimate built from creatinine, age and sex — and the estimate is better than the raw creatinine it comes from, for a reason worth understanding.
- TSH Normal Range: 0.4–4.0 mIU/L, and the Number Moves BackwardsTSH runs opposite to the gland it measures. High TSH means the thyroid is underactive, and that inversion catches almost everyone reading their own result.
- Cholesterol Numbers: What Total, LDL, HDL and Triglycerides MeanA lipid panel reports four numbers and the one printed largest — total cholesterol — is the least useful of them.