PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC5922674
How to interpret thyroid function tests - PMC
If the former, then changes in binding proteins can confound interpretation of results: T4 and T3 are heavily protein bound; thus, total, but not free, hormone measurements are affected by alterations in binding protein status (eg exogenous oestrogen therapy and pregnancy increase TT4 levels through elevation of T4-binding globulin (TBG)). In all patients in whom thyroid function testing is being considered, it is important to keep the following in mind. Thyroid status. Ideally, results of TFTs should confirm one’s clinical suspicion, namely that the patient is euthyroid, hypothyroid or hyperthyroid. Reassessment of clinical status is particularly important when faced with an unexpected TFT result because it provides an important clue to the test (TSH, T4 and/or T3) that is likely to be discordant and guides further investigation (see below).
Cleveland Clinic
my.clevelandclinic.org › health › diagnostics › 24235-thyroxine-t4-test
T4 (Thyroxine) Test: What It Is, Function, Purpose & Levels
July 21, 2025 - This is a lack of T4 production due to an issue with your thyroid that’s causing your pituitary gland to release excess TSH to try to stimulate your thyroid into making more T4. Having high TSH and high T4 levels may indicate that you have an issue with your pituitary gland that’s causing it to release too much TSH, and thus triggering your thyroid to make excess T4.
High TSH and high T4
For almost one year I’m having results come back at varying times with both high TSH and T4 which contradict one another. High TSH Hypothyroidism (which I’ve been for 26 years) and high T4 indicates hyperthyroidism. My endocrinologist and her team act like they’ve never seen this. More on connect.mayoclinic.org
What causes high TSH but normal T4?
The day before my blood test I didn't eat breakfast until 530 am More on reddit.com
73
21
August 26, 2022What does this mean? Slightly high T4 and high TSH.
You had over range or near TSH all of last year. High TSH indicates some type of thyroid disease. What time of day were all of these blood draws? High TSH with high in range FT4 could be due to Hashimoto's and/or, possibly low FT3. T4 is converted into T3. Hashimoto's can cause problems with this conversion. You'll have to retest, since TSH, FT4, and FT3 all need to be tested as a group. Blood draw needs to be first thing in the morning. Both thyroid antibodies (TPO/ab and TG/ab) need to be tested to rule out Hashimoto's. It's very important to know if you have an autoimmune disease and if your hypothyroidism is caused by autoimmune Hashimoto's. Which type of thyroid replacement hormones and doses did you try when you experienced intolerance? What sort of symptoms did you experience, and what were your TSH and FT4 when you tried thyroid replacement hormone? More on reddit.com
28
4
October 8, 2021High TSH, but normal T3 and T4
Absolutely we can have hypo symptoms when TSH is High, but T4 and T3 are normal! The time to begin treating hypo is when TSH is High. If we wait until T4 and T3 are Low, then we may develop very unpleasant symptoms and possibly even other health conditions. I briefly went clinically hypo (Low T4 and Low T3) and had awful digestive symptoms and heart burn. I had never had heart burn before! I also felt depressed and unmotivated. I was surprised by how long it took my mental health to get back to normal. When you are being diagnosed with hypo, they often want to re-check your thyroid hormone levels to confirm that TSH is staying Abnormally High. Once they confirm this, then they are likely to prescribe thyroid medication. They know that the High TSH wasn’t just a fluke, that it’s here to stay, and that you can benefit from medication. If you are pregnant or trying to conceive, TSH needs to be below 2.5. If you are pregnant then Dr should likely prescribe thyroid medication immediately instead of waiting to re-test. The fetus uses our thyroid hormone to grow and develop normally during 1st trimester. Sometime after first trimester you still need normal range TSH to be as healthy as you can be, but baby’s thyroid gland will likely be producing thyroid hormone for baby. More on reddit.com
89
21
February 28, 2023Videos
01:43
TSH and T3/T4 - Whats the difference? Lab Values/ABG - Shorts | ...
02:11
TSH and Thyroid Function Tests | UCLA Endocrine Center - YouTube
04:48
Hyperthyroidism (Overactive Thyroid): Symptoms, Causes & Diagnosis ...
16:10
19 Signs of HYPERTHYROIDISM (Graves Disease) You Can See: Doctor ...
02:36
Thyroid Stimulating Hormone | UCLA Endocrine Center - YouTube
03:27
I Have Symptoms of Hypothyroidism but My TSH Is Normal | UCLA ...
American Thyroid Association
thyroid.org › home › thyroid function tests
Thyroid Function Tests | American Thyroid Association
June 8, 2020 - The amount of TSH that the pituitary sends into the bloodstream depends on the amount of T4 that the pituitary sees. If the pituitary sees very little T4, then it produces more TSH to tell the thyroid gland to produce more T4. Once the T4 in the bloodstream goes above a certain level, the pituitary’s production of TSH is shut off.
Mayo Clinic
mayoclinic.org › diseases-conditions › hypothyroidism › diagnosis-treatment › drc-20350289
Hypothyroidism (underactive thyroid) - Diagnosis and treatment - Mayo Clinic
December 10, 2022 - Understand what happens when your thyroid is underactive and learn about treatment for this condition.
NHS
nhs.uk › conditions › overactive-thyroid-hyperthyroidism › diagnosis
Overactive thyroid (hyperthyroidism) - Diagnosis - NHS
thyroxine (T4) – another of the ... person of your age. A low level of TSH and high levels of T3 and/or T4 usually means you have an overactive thyroid....
University of Michigan Health
uofmhealth.org › home › our care › specialties & services › hyperthyroidism & graves’ disease
Hyperthyroidism & Graves’ Disease | University of Michigan Health
A high TSH level indicates that the body does not have enough thyroid hormone. A TSH level lower than normal indicates there is usually more than enough thyroid hormone in the body and may indicate hyperthyroidism.
Advocate Health
adscresources.advocatehealth.com › does-tsh-tell-the-whole-story
Does TSH tell the whole story? | Adult Down Syndrome Center
This page shares information on thyroid testing for individuals with Down syndrome.
Mayo Clinic Connect
connect.mayoclinic.org › discussion › high-tsh-and-high-t4
High TSH and high T4 | Mayo Clinic Connect
September 9, 2023 - High TSH means your thyroid is slow. That with a high T4 is odd but it’s possible you are not absorbing it or you might have an allergy to it like my sister and I. Additionally make sure you are not on Biotin when your thyroid is checked again. My sister and I just take T3 because T4 either ...
American Academy of Family Physicians
aafp.org › pubs › afp › issues › 1998 › 0215 › p776.html
Subclinical Hypothyroidism: Deciding When to Treat | AAFP
February 15, 1998 - While screening patients for thyroid disease, physicians often find increased thyrotropin-stimulating hormone (TSH) levels in patients whose free thyroxine (T4) levels are not below normal. This state, termed "subclinical hypothyroidism," is most ...
UCLA Health
uclahealth.org › medical-services › surgery › endocrine-surgery › conditions-treated › thyroid › normal-thyroid-hormone-levels
Normal Thyroid Hormone Levels - Endocrine Surgery | UCLA Health
A normal Total T3 level in adults ranges from 80-220 ng/dL. Free T3 assays are often unreliable and not routinely used to assess thyroid function. Primary Hypothyroidism A high TSH and low thyroid hormone level (e.g.
American Thyroid Association
thyroid.org › home › patients portal › clinical thyroidology for the public › january 2024 › vol 17 issue 1 p.13-14
Increased FT4 and incompletely suppressed TSH levels are mainly related to levothyroxine use
January 8, 2024 - TSH levels are opposite to FT4 levels. When the thyroid is underactive and FT4 levels are low, TSH levels go up. When the thyroid is overactive and FT4 levels are high, TSH levels go down.
Oxford Academic
academic.oup.com › jcem › article › 109 › 4 › 1094 › 7439666
Approach to the Patient With Raised Thyroid Hormones and Nonsuppressed TSH | The Journal of Clinical Endocrinology & Metabolism | Oxford Academic
March 15, 2024 - It is well recognized that in some thyroxine-treated patients with goitrous or dysgenetic CH, but without any additional defect in genes mediating TH action, circulating TSH remains raised despite FT4 concentrations being within the normal range, such that a higher dosage of T4 (with resultant elevated FT4 concentrations) is required to normalize TSH (67, 68).
British Thyroid Foundation
btf-thyroid.org › thyroid-function-tests
Thyroid function tests
BTF patient leaflet on thyroid function tests
NPS
nps.org.au › assets › fa172d98f69769b8-d253ad676cdd-6f85b7bb7adf6b07a897038044b88b7bd93037a211bf0756d6ca9a0a05fd.pdf pdf
12 | Volume 34 | NUMBER 1 | february 2011 www.australianprescriber.com
It is not uncommon to find a raised TSH but normal free T4. In most cases this suggests autoimmune thyroid disease. This subclinical hypothyroidism is more likely to progress to · overt hypothyroidism when higher levels of TSH and thyroid
North Bristol NHS Trust
nbt.nhs.uk › sites › default › files › TFT strategy - no appendix.pdf pdf
BLOOD SCIENCES DEPARTMENT OF CLINICAL BIOCHEMISTRY
FT3/FT4 are increased and TSH is normal or high.
RACGP
racgp.org.au › afp › 2012 › august › hypothyroidism
RACGP - Hypothyroidism - Investigation and management
April 9, 2012 - AetiologyIodine deficiency remains the most common cause of hypothyroidism worldwide.4 However, in Australia and other iodine replete countries, autoimmune chronic…
RACGP
www1.racgp.org.au › ajgp › 2021 › january-february › thyroid-disease-using-diagnostic-tools-effectively
RACGP - AJGP (Australian Journal of General Practice)
Rational investigation of thyroid disease requires careful avoidance of over-investigation of minor abnormalities balanced with prompt diagnosis of serious health conditions.
British Thyroid Foundation
btf-thyroid.org › subclinical-thyroid-disease
Subclinical thyroid disease
Learn about subclinical (borderline) thyroid conditions
Pathology Tests Explained
pathologytestsexplained.org.au › ptests.php
Thyroid stimulating hormone (TSH) | Pathology Tests Explained
TSH stimulates your thyroid to make thyroid hormones T4 and T3. If hormone levels are too high, it tells the thyroid to make less.
Children's Mercy Kansas City
childrensmercy.org › health-care-providers › pediatrician-guides › endocrinology › abnormal-thyroid
Abnormal Thyroid - Children's Mercy
TSH is the single most sensitive test used to diagnose primary hypothyroidism (high TSH) or hyperthyroidism (low TSH). In these situations, free T4 (FT4) is low or high respectively; when this occurs, the diagnosis of an overt thyroid illness ...