Can this result diagnose a condition on its own?

No. This result should be interpreted with related hormones, symptoms, and clinical context.

Which reference range should I use?

Use the reference interval provided by the laboratory that performed your test.

When should I discuss the result with a healthcare professional?

Results that are clearly outside range, persistent, or inconsistent with symptoms should be reviewed by a healthcare professional.

Information about a laboratory test

TSH in Pregnancy: How Is It Interpreted?

TSH in pregnancy should not be interpreted exactly like a nonpregnant result because hCG and thyroid physiology change during pregnancy.

Test summary

Test name: TSH
Abbreviations: TSH, Thyrotropin
Category: Endocrinology / Thyroid
Panel: Thyroid Function Tests
Specimen: Serum / plasma
Common units: mIU/L, µIU/mL

What does the test measure?

Measures TSH, a pituitary hormone that signals the thyroid gland how much thyroid hormone to make.

Why is the test ordered?

Commonly used as the first-line test for thyroid function, suspected hypo- or hyperthyroidism, and monitoring thyroid treatment.

Information about a low result

Low TSH may occur when thyroid hormone levels are excessive, but pituitary disorders, severe illness, and medicines can also affect it.

Information about a high result

High TSH may occur when thyroid hormone production is insufficient; age and treatment status can change interpretation.

Reference and clinical context

Use the reference interval printed on your own laboratory report first. Hormone results may vary with the assay, age, sex, pregnancy, menstrual-cycle phase, and sampling time.

Reference range 1

>= 0.4 – <= 4.8 µU/mL

Population: General
Specimen: Serum / plasma

Example reference interval

MedlinePlus example. TSH may vary by laboratory, time of day, and age.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

If the laboratory provides pregnancy- or trimester-specific intervals, those should be preferred. ATA guidance emphasizes trimester-specific interpretation.

Related specialties

Endocrinology
Internal Medicine
Obstetrics and Gynecology
Pediatric Endocrinology

Frequently asked questions

Sources

Thyroid Tests — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
U.S. government medical reference · 2026 · TSH, T4, T3 and thyroid-antibody testing; interpretation as a group · Verified: Aug 11, 2026
Hashimoto's Disease — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
U.S. government medical reference · 2026 · Hashimoto disease; TSH/T4/T3 and TPO antibody context · Verified: Aug 11, 2026
Graves' Disease — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
U.S. government medical reference · 2026 · Graves disease; thyroid-stimulating immunoglobulin / receptor-antibody context · Verified: Aug 11, 2026
TSH (Thyroid-stimulating hormone) Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · TSH purpose; high/low context; effects of age, illness and medicines · Verified: Aug 11, 2026
TSH test — U.S. National Library of Medicine (MedlinePlus)
Government medical encyclopedia · 2026 · Example TSH reference interval; time-of-day and older-age caveats · Verified: Aug 11, 2026
Thyroxine (T4) Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Total/free T4 testing and thyroid-function context · Verified: Aug 12, 2026
Triiodothyronine (T3) Tests — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2023 · Total/free T3 testing and thyroid-function context · Verified: Aug 12, 2026
Thyroid Antibodies — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2023 · TPOAb, TgAb and TRAb; autoimmune-thyroid context · Verified: Aug 11, 2026
Thyroid Function Tests — American Thyroid Association
Professional society patient guidance · 2026 · TSH, free T4 and T3 interpretation; free vs total hormone context · Verified: Aug 11, 2026
Hyperthyroidism in Pregnancy / Pregnancy Thyroid Guidance — American Thyroid Association
Professional society patient guidance · 2026 · Pregnancy-specific and trimester-specific thyroid reference context · Verified: Aug 11, 2026
Prolactin Levels — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Prolactin purpose; pregnancy, medicines and sampling-time context · Verified: Aug 11, 2026