Skip to content

Follicle Stimulating Hormone (FSH) – Serum

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.

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
21275-3
Short code
FSH 15M p GnRH SerPl-aCnc
Synonyms
FSH 15M p GnRH 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 Is FSH Used For?

FSH levels are often checked to evaluate fertility, hormone balance, and potential issues with the ovaries or testes. It may also be used to monitor conditions like polycystic ovary syndrome (PCOS) or endocrine disorders.

Who Might Need This Test?

Doctors may order an FSH test if you’re experiencing irregular menstrual cycles, difficulty getting pregnant, low libido, or signs of early menopause. Men might also have it if they have low sperm counts or other fertility concerns.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. You’ll need to fast for a few hours before the test, but this depends on your doctor’s instructions.

What Are Common Results?

Results are interpreted based on your age, sex, and medical history. High or low FSH levels can signal different health concerns, so your doctor will discuss them with you.

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 test be done during my menstrual cycle?
FSH levels can fluctuate slightly with your menstrual cycle, so your doctor may choose the best time to test based on your symptoms or treatment plan. Some tests are done during the follicular phase (early in your cycle) to get more accurate results.
What if my FSH level is outside of the usual range?
If your FSH is higher or lower than expected, your doctor will review your symptoms and other test results to determine if there’s an underlying condition. Additional tests or further evaluation may be needed.
Can lifestyle changes affect my FSH levels?
Yes, factors like stress, poor sleep, obesity, and certain medications can influence hormone levels. Maintaining a healthy lifestyle and discussing any concerns with your doctor can help support your overall reproductive health.
  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