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FSH (Follicle Stimulating Hormone) – Serum/plasma, Substance Concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures your levels of follicle-stimulating hormone, a hormone produced by the pituitary gland that plays a key role in reproductive health.

Quick summary

["FSH helps regulate egg development in women and sperm production in men."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
27880-4
Short code
FSH sp6 p chal SerPl-aCnc
Synonyms
FSH sp6 p chal SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
3.5
Ref high
12.5
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83001
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does FSH Measure?

FSH is measured in the blood (either serum or plasma) and reflects your body’s hormone balance. It helps doctors assess reproductive function, fertility, and potential hormonal imbalances.

When Might You Need This Test?

Doctors order FSH tests to evaluate conditions like infertility, irregular menstrual cycles (in women), low testosterone (in men), or signs of early menopause. It may also be checked during fertility treatments or to monitor hormone-related diseases.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed using an immunoassay method to detect FSH levels.

What Are Common Results and Their Meanings?

Results are typically reported as a concentration value (e.g., IU/L), but exact ranges can vary by lab. High or low FSH levels may indicate different health concerns, so results should always be discussed with your healthcare provider.

Reference range

Follicular: 3.5-12.5 mIU/mLN/A

Specimen: serum

For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: FSH plays a critical role in reproductive health. Elevated FSH in women may signal early menopause, ovarian dysfunction, or polycystic ovary syndrome (PCOS). In men, it can indicate low testosterone or hypogonadism. Low FSH may suggest pituitary gland issues or other hormonal disorders.

Short name

FSH Level

Frequently asked questions

Why might my FSH levels be checked during pregnancy?
FSH is not typically checked during pregnancy unless there are concerns about hormonal imbalances affecting fertility or pregnancy outcomes. If you’re planning pregnancy, your doctor may recommend testing before conception.
What can affect my FSH test results?
Several factors can influence FSH levels, including stress, illness, certain medications (like birth control or thyroid medications), and hormonal imbalances. It’s important to inform your doctor about all medications and health conditions before the test.
Can lifestyle changes impact FSH levels?
Yes, lifestyle factors such as diet, exercise, weight management, and smoking can influence hormone levels, including FSH. Maintaining a healthy weight, reducing stress, and avoiding smoking may support balanced hormone function.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy