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Follicle Stimulating Hormone (FSH) – Serum, Plasma

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

This test measures the amount of Follicle Stimulating Hormone (FSH) in your blood. FSH plays a key role in hormone regulation, particularly in reproductive health for both men and women.

Quick summary

["FSH helps balance hormones that affect fertility and hormone production in your body."]

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

Key facts at a glance

LOINC
83098-4
Short code
FSH SerPl IA-aCnc
Synonyms
FSH SerPl IA-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
Method
ia
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 Is FSH Used For?

FSH testing is often done to evaluate reproductive function, diagnose hormonal imbalances, and assess conditions like infertility, irregular menstrual cycles, or symptoms of early menopause. It may also be used to monitor treatment for hormone-related disorders.

Who Might Need This Test?

Your healthcare provider may recommend an FSH test if you have concerns about fertility, irregular periods, low libido, or symptoms like hot flashes. Men may also have it checked for issues like low testosterone or unexplained infertility.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. You’ll typically fast for 8–12 hours before the test, but your provider will give specific instructions. The sample is sent to a lab for analysis using an immunoassay method to measure FSH levels.

What Do My Results Mean?

Results can vary based on age, sex, and medical history. High or low FSH levels may signal underlying conditions, but your provider will interpret results in the context of your overall health and symptoms.

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.

◆Associated findings1

Short name

FSH Level

Frequently asked questions

Why might my FSH level be checked during pregnancy or fertility planning?
FSH is crucial for egg development in women and sperm production in men. Elevated or low levels may indicate issues like premature ovarian insufficiency (POI), polycystic ovary syndrome (PCOS), or other hormonal disorders. Your provider may also check FSH during fertility treatments to monitor progress.
What could abnormal FSH levels suggest?
High FSH levels in women may signal early menopause, ovarian dysfunction, or conditions like PCOS. In men, elevated FSH can sometimes accompany low testosterone or kidney disease. Low FSH may indicate pituitary disorders or hypogonadism, though other tests would confirm the diagnosis.
Does fasting affect FSH test results?
Yes, fasting for 8–12 hours before the test can help ensure accurate results, as hormones like FSH fluctuate throughout the day. Follow your provider’s instructions to avoid food or alcohol before testing.
  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