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FSH (Follicle Stimulating Hormone) – Serum, Quantitative Immunoassay

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

This test measures the amount of follicle-stimulating hormone (FSH) in your blood. FSH is a hormone produced by the pituitary gland that plays a key role in reproductive health, including egg and sperm development.

Quick summary

["FSH helps regulate fertility and hormone balance, often checked in reproductive health evaluations."]

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

Key facts at a glance

LOINC
21279-5
Short code
FSH 1.5h p chal SerPl-aCnc
Synonyms
FSH 1.5h 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

Why This Test Is Done

Your doctor may order an FSH test to evaluate fertility issues, assess hormonal imbalances, or check for conditions like premature ovarian insufficiency (POI) or hypogonadism. It may also be used in monitoring conditions like polycystic ovary syndrome (PCOS) or after treatments affecting hormone levels.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab for analysis using an immunoassay method to detect FSH levels accurately. You may be asked to fast for 8–12 hours before the test if instructed by your doctor.

What to Expect Before the Test

No special preparation is typically required beyond standard blood draw precautions. If you’re on hormonal medications, your doctor may advise stopping them temporarily to avoid interfering with results.

What the Results Mean

Results are interpreted based on your age, sex, and medical history. High or low FSH levels can signal potential reproductive or endocrine disorders, but individual results vary widely.

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

What Does an Elevated FSH Level Indicate?
Elevated FSH levels may suggest conditions like early menopause, ovarian insufficiency, or certain genetic disorders affecting hormone production. In men, it could indicate hypogonadism or other pituitary issues.
What Does a Low FSH Level Indicate?
Low FSH levels might be seen in conditions like pituitary tumors, hypothyroidism, or congenital deficiencies in hormone production. It can also occur in early puberty or during certain medications.
How Often Should I Get This Test?
The frequency depends on your symptoms, medical history, and treatment plan. Your doctor will determine if repeat testing is needed, such as every 3–6 months for monitoring reproductive health or hormonal conditions.
  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