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FSH (Follicle Stimulating Hormone) in serum/plasma, measured by immunoassay (CLIA)

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

This test measures the amount of follicle-stimulating hormone in your blood. FSH helps regulate the menstrual cycle and production of eggs in women, and sperm in men.

Quick summary

["FSH helps guide reproductive health and hormone balance."]

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

Key facts at a glance

LOINC
25650-3
Short code
FSH sp7 p chal SerPl IRP2-aCnc
Synonyms
FSH sp7 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 This Test Is Done

Your healthcare provider may order an FSH test to check for hormonal imbalances, diagnose fertility issues, or evaluate conditions affecting the ovaries, testes, or pituitary gland. It’s often used alongside other hormone tests, like estrogen or testosterone, to get a full picture of reproductive health.

What to Expect Before the Test

No special preparation is needed for this blood test. You may be asked to fast for 8–12 hours before the draw if your lab uses a fasting protocol for hormone testing. Wear comfortable clothing and plan to rest after the draw.

What Happens During the Test

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

What the Results Mean

Results are interpreted based on your sex, age, and overall health. High or low FSH levels can signal conditions like early menopause, polycystic ovary syndrome (PCOS), or pituitary disorders. Your provider will discuss findings in the context of your symptoms and medical history.

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’s Role in Health

Short name

FSH Level

Frequently asked questions

What could cause abnormal FSH levels?
High FSH levels might indicate early menopause, ovarian dysfunction, or conditions like PCOS. Low FSH could suggest pituitary tumors, hypothyroidism, or genetic disorders affecting hormone production. Always consult your provider for personalized interpretation.
How often should I get this test?
Your provider will determine testing frequency based on your symptoms, age, and medical history. Some women get FSH tests during fertility evaluations or during perimenopause. Never repeat a test without guidance.
Does fasting affect FSH test results?
Yes, fasting for 8–12 hours before the test may slightly influence FSH levels, as hormones can fluctuate with food. If fasting is required, follow your provider’s instructions to ensure accurate 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