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FSH (Follicle Stimulating Hormone) in Serum

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

This test measures the levels of follicle-stimulating hormone (FSH) in your blood. FSH plays a key role in regulating the reproductive system, including egg and sperm production.

Quick summary

["FSH helps guide fertility and hormone balance in both men and women."]

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

Key facts at a glance

LOINC
25648-7
Short code
FSH sp5 p chal SerPl IRP2-aCnc
Synonyms
FSH sp5 p chal SerPl IRP2-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
nd-irp
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 Is This Test Done?

Your healthcare provider may order an FSH test to check for reproductive hormone imbalances, evaluate fertility issues, or monitor conditions like polycystic ovary syndrome (PCOS), menopause, or hypogonadism. It can also help diagnose or monitor conditions like Klinefelter syndrome in men or ovarian dysfunction in women.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the blood draw if your lab requires it. Wear a loose shirt for easy access to your arm.

What Happens During the Test?

A healthcare professional will insert a small needle into your arm to draw blood. You may feel a brief pinch, but it’s usually over quickly. The blood sample is sent to a lab for analysis.

What Are Possible Results?

Results are compared to a general reference range, which can vary slightly by lab. High or low FSH levels may suggest hormonal imbalances or underlying health conditions.

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 Levels and Health

Short name

FSH Serum

Frequently asked questions

What Does My FSH Level Mean?
High FSH levels may indicate early menopause, ovarian failure, or conditions like PCOS. Low FSH could signal pituitary disorders, hypogonadism, or certain genetic conditions. Always discuss your results with your doctor for personalized interpretation.
How Often Should I Get This Test?
Your doctor will determine the frequency based on your symptoms, medical history, or treatment plan. Regular monitoring may be needed if you’re undergoing fertility treatments or managing reproductive health conditions.
Can Diet or Exercise Affect FSH Levels?
Dietary factors like calorie intake (especially in women) and exercise can influence FSH levels. Stress, weight fluctuations, and certain medications may also play a role. Talk to your doctor about lifestyle factors that might impact your results.
  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