Free T4 (fT4) normal range by age:
Newborns (0–6 days): 11.0 – 32.0 pmol/L
6 days to 3 months: 11.5 – 28.3 pmol/L
3 months to 1 year: 11.9 – 25.6 pmol/L
1–6 years: 12.3 – 22.8 pmol/L
6–11 years: 12.5 – 21.5 pmol/L
11–18 years: 12.6 – 21.0 pmol/L
Adults (18+ years): 10.0 – 22.0 pmol/L
Total T4 (TT4) normal range by age:
Newborns (up to 14 days): 11.8 – 22 mcg/dL (152–292 nmol/L)
Infants (7–14 days): 10 – 16 mcg/dL (126–214 nmol/L)
Infants (1–12 months): 8 – 16 mcg/dL (101–213 nmol/L)
Children (1–5 years): 7 – 15 mcg/dL (94–194 nmol/L)
Children (5–10 years): 6.0 – 13.0 mcg/dL (83–172 nmol/L)
Children (10–15 years): 5 – 12 mcg/dL (72–151 nmol/L)
Adults (18+ years): 5.4 – 11.5 mcg/dL (57–148 nmol/L)
Note: Normal ranges vary by laboratory and testing method. Always refer to the reference range provided on your lab report. Values may also differ slightly based on gender and iodine intake in the population.
Asian Heart Institute
asianheartinstitute.org › home › tsh, t3 & t4 test: normal range by age, gender & report meaning
TSH, T3, T4 Normal Range by Age & Gender | Thyroid Test Guide
September 17, 2025 - Q7: What does a TSH of 29 mean? A: A TSH score of 29 mIU/L is considered very high. It usually indicates underactive thyroid (hypothyroidism). Treatment with thyroid hormone may be required after clinical evaluation. Q: What are T3 and T4 normal values and how do they vary by age?
Medscape
emedicine.medscape.com › tools & reference › laboratory medicine
Thyroxine: Reference Range, Interpretation, Collection and Panels
November 10, 2025 - Reference ranges for total thyroxine (TT4) are as follows: In newborns up to age 14 days: 11.8–22.
Medical News Today
medicalnewstoday.com › articles › t4-levels
T4 levels: What is a normal T4 level, and how it is tested?
October 23, 2023 - The treatment for abnormal T4 levels varies depending on whether the levels are too low or too high. ... 4.6% of U.S. citizens aged 12 years and older have hypothyroidism, and most of these cases are mild.
What are T3 and T4 normal values and how do they vary by age?
Typical reference values for adults are T3 ≈ 80-200 ng/dL and T4 ≈ 5.0-12.0 µg/dL. In children or during puberty, these levels may be higher. Hormonal changes (such as pregnancy) can also affect these values.
asianheartinstitute.org
asianheartinstitute.org › home › tsh, t3 & t4 test: normal range by age, gender & report meaning
TSH, T3, T4 Normal Range by Age & Gender | Thyroid Test Guide
What is the normal TSH range for pregnant women?
During pregnancy, many labs consider TSH to be normal if it stays between 0.2 to 3.5 mIU/L, especially in the first trimester. Always consult your obstetrician or endocrinologist.
asianheartinstitute.org
asianheartinstitute.org › home › tsh, t3 & t4 test: normal range by age, gender & report meaning
TSH, T3, T4 Normal Range by Age & Gender | Thyroid Test Guide
What are T3 and T4?
T3 (triiodothyronine) and T4 (thyroxine) are thyroid hormones responsible for regulating metabolism, energy, and overall bodily functions.
asianheartinstitute.org
asianheartinstitute.org › home › tsh, t3 & t4 test: normal range by age, gender & report meaning
TSH, T3, T4 Normal Range by Age & Gender | Thyroid Test Guide
American Thyroid Association
thyroid.org › home › patients portal › clinical thyroidology for the public › february 2024 › vol 17 issue 2 p.5-6
The “new normal” for thyroid function test ranges
February 23, 2024 - BACKGROUND The normal range of thyroid function tests is determined by measuring Free T4 and TSH levels in a population of healthy adults with no thyroid problems. Those results in the middle 95% are considered the normal range; the 2.5% above ...
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC5794073
Age- and gender-specific reference intervals of TSH and free T4 in an iodine-replete area: Data from Korean National Health and Nutrition Examination Survey IV (2013–2015) - PMC
This result is in accord with other studies about FT4, showing either no change or a minimal decrease in FT4 with age [10], although some reports suggested that the differences were too small to have clinical significance [31]. Recently, there were some reports showing that increased TSH and decreased free thyroid hormone are associated with prolonged life span in some populations [12,32]. These reports support the suggestion that age-specific reference ranges of TSH should be set in order to avoid over-treatment. Most clinicians would agree to the need to establish reference intervals of thyroid hormones with consideration of age, gender, ethnicity, and iodine intake. However, they still use the values provided by the guidelines or commercial kits manufacturers because of the lack of regional or population data.
WebMD
webmd.com › a to z guides › reference
What Is a T4 (thyroxine) Blood Test?
March 16, 2024 - Normal range on the free T4 test vary by age, sex assigned at birth, and lab testing method, but in general, they are as follows:
Mayo Clinic Laboratories
pediatric.testcatalog.org › show › T4
T4 (Thyroxine), Total Only, Serum - Mayo Clinic Laboratories | Pediatric Catalog
Values below 4.5 mcg/dL in adults or below the age-related cutoffs in children are seen in hypothyroidism, myxedema, cretinism, chronic thyroiditis, and occasionally, subacute thyroiditis. Increased total T4 (thyroxine) is seen in pregnancy and patients who are on estrogen medication.
UCSF Health
ucsfhealth.org › medical-tests › free-t4-test
Free T4 test
August 6, 2024 - You may be having symptoms of ... in the normal range. The TSH test may help determine if your symptoms are related to thyroid disease. Talk to your provider about your symptoms. To fully understand results of the free T4 test, results of other thyroid blood tests, such as TSH or T3, may be needed. Test results may also be affected by pregnancy, ...
Newcastle Hospitals Laboratories
laboratories.newcastle-hospitals.nhs.uk › home › free t4, serum
Free T4, serum - Newcastle Hospitals Laboratories
December 24, 2024 - Free T4 is measured as part of a thyroid function test with TSH, or may be cascaded following an abnormal TSH result. ... Low TSH with raised FT4 (and/or FT3) is consistent with primary hyperthyroidisim. Raised TSH with low FT4 is consistent with hypothyroidism. ‘Sub-clinical’ or borderline hypo/hyperthyroidism can be associated with a FT4 within the reference range but abnormal TSH. Low FT4 with an inappropriatly low or normal TSH can be associated with secondary hypothyroidism.
PLOS
journals.plos.org › plosone › article
Age- and gender-specific reference intervals of TSH and free T4 in an iodine-replete area: Data from Korean National Health and Nutrition Examination Survey IV (2013–2015) | PLOS One
February 1, 2018 - In the reference population, mean FT4 was 1.25 ± 0.003 ng/dL (16.09 ± 0.039 pmol/L) (Table 3). After age 20 years, FT4 decreased significantly with age (P for trend < 0.0001). Mean FT4 in males (1.29 ± 0.003 ng/dL, 16.60 ± 0.039 pmol/L) ...
SynappseHealth
synappsehealth.com › en › articles › i › the-scope-of-tsh-and-ft4-standards-for-children-and-adults
The range of TSH and FT4 norms for children and adults
January 13, 2019 - * according to the recommendations of the National Consultant in the field of endocrinology, the suggested value of TSH for adults is about 3 μUU / ml as the upper limit of the norm; * in the elderly (> 80 years): 0.4-10 μIU / ml (provided ...
Blazma
blazma.com › blogs › 52
What Are the Normal Thyroid Hormone Levels?
Generally, the normal range for TSH levels is between 0.4 - 4.0 milliunits per liter (mU/L), but various factors can affect its level, such as gender, age, pregnancy, and certain diseases.
Amegroups
tp.amegroups.org › article › view › 80097 › html
Age- and sex-specific reference intervals for thyroid hormones in a Chinese pediatrics: a prospective observational study of 1,279 healthy children - Yao - Translational Pediatrics
September 29, 2021 - For FT3 and T3, the reference range for males was higher than females, and the reference range of T4 for males was narrower and higher than for females (P2.5–P97.5: 72.33–171.60 vs.
MyDiagnostics
mydiagnostics.in › thyroid › what is t4? thyroxine test, normal ranges & what high levels mean
What Is T4? Thyroxine Test, Normal Ranges & What High Levels Mean – MyDiagnostics
August 8, 2025 - Typically, the normal T4 range ... depending on certain factors. The T4 normal levels for children up to 5 years of age range between 0.8 to 2.8 ng/dL....
Apollo 24x7
apollo247.com › blog › article › t3-t4-tsh-normal-range-how-to-maintain-healthy-thyroid-hormone-levels
T3, T4 TSH Normal Range: How To Maintain Healthy Thyroid Hormone Levels?
January 21, 1970 - The normal range of thyroid hormones varies based on age, gender, and individual health factors.
Cleveland Clinic
my.clevelandclinic.org › health › diagnostics › 24235-thyroxine-t4-test
T4 (Thyroxine) Test: What It Is, Function, Purpose & Levels
July 21, 2025 - The normal measurement range for that test. Information that indicates if your result is normal or abnormal, or high or low. Normal levels of free T4 vary based on your age.
UCLA Health
uclahealth.org › medical-services › surgery › endocrine-surgery › conditions-treated › thyroid › normal-thyroid-hormone-levels
Normal Thyroid Hormone Levels - Endocrine Surgery | UCLA Health
FT4 normal values are 0.7 to 1.9ng/dL. Individuals taking medications that modify thyroid hormone metabolism and those with a history of thyroid cancer or pituitary disease may be optimally managed with a different normal FT4 range.
Gloshospitals
gloshospitals.nhs.uk › our-services › services-we-offer › pathology › tests-and-investigations › thyroid-function-tests-tsh-ft4-ft3
Thyroid Function Tests (TSH, FT4, FT3)
Age-related reference ranges for children apply as displayed in the table below. Please note there are also pregnancy related reference ranges displayed below. ... Paediatric Ranges: Bristol Children's Hospital (adopted to harmonise ranges). Pregnancy Ranges: Reference Intervals for Children and Adults - Elecsys® Thyroid Tests’, Roche Diagnostics Limited, 2021
Mount Sinai
mountsinai.org › health-library › report › hypothyroidism
Hypothyroidism Information | Mount Sinai - New York
Presence of other medical conditions that may benefit from or be worsened by thyroid replacement therapy. Pregnancy status. Medications that the person is also taking to treat other conditions, which may interfere with absorption of thyroxine (T4) from the small intestine. ... Considerable debate exists about whether to treat people with subclinical hypothyroidism (TSH levels in the upper range of normal levels or slightly higher than normal, normal T4 levels, and no obvious symptoms).
NHS
nhs.uk › conditions › overactive-thyroid-hyperthyroidism › diagnosis
Overactive thyroid (hyperthyroidism) - Diagnosis - NHS
Doctors may refer to these measurements as "free" T3 and T4 (FT3 and FT4). What's considered normal varies depending on things such as your age and the exact testing technique used by the laboratory.