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FSH (Follicle Stimulating Hormone) in serum/plasma

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

This test measures the amount of follicle-stimulating hormone in your blood. FSH plays a key role in regulating reproductive function in both men and women.

Quick summary

["FSH helps balance hormone production and supports fertility."]

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

Key facts at a glance

LOINC
25646-1
Short code
FSH sp3 p chal SerPl IRP2-aCnc
Synonyms
FSH sp3 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 hormonal imbalances, evaluate fertility issues, diagnose conditions affecting the ovaries or testes, or monitor treatment for hormone-related disorders. It may also be used in menopause assessment or to screen for conditions like polycystic ovary syndrome (PCOS).

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 test involves fasting-related measurements. Wear comfortable clothing and plan to stay near the testing site for a short time.

How the Test Is Performed

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but it usually doesn’t cause significant discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are interpreted based on your age, sex, and medical history. High or low FSH levels can indicate different health concerns, such as early menopause, ovarian dysfunction, or hypogonadism. Your doctor will discuss the results with you in the context of your overall health.

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

Short name

FSH Level

Frequently asked questions

What Are Common Causes of Abnormal Results?
Abnormally high FSH levels may suggest conditions like premature ovarian insufficiency (POI), ovarian failure, or certain genetic disorders. Low FSH could indicate hypothyroidism, pituitary disorders, or other hormonal imbalances. Always consult your healthcare provider for personalized interpretation.
How Often Should I Get This Test?
Your doctor will determine how often you need this test based on your symptoms, medical history, and treatment plan. Regular monitoring may be recommended if you’re undergoing fertility treatments or managing a chronic condition affecting hormone levels.
Can Diet or Lifestyle Affect FSH Levels?
While diet and lifestyle factors like stress, weight, and exercise can influence hormone balance, they don’t directly alter FSH test results. Avoiding caffeine or alcohol before the test may help ensure accurate results, but follow your provider’s specific instructions.
  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