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Follicle Stimulating Hormone (FSH) – Serum, Plasma, or 24-Hour Urine Collection (as specified by lab protocol)

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

This test measures your body’s levels of follicle-stimulating hormone, a key hormone involved in reproductive health, including egg and sperm production.

Quick summary

["FSH helps regulate 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
25642-0
Short code
FSH sp1 p chal SerPl IRP2-aCnc
Synonyms
FSH sp1 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 doctor may order an FSH test to check for hormonal imbalances, diagnose fertility issues, evaluate conditions like polycystic ovary syndrome (PCOS), or monitor treatment for hormone-related disorders. It can also help assess ovarian or testicular function in adults and children.

What to Expect Before the Test

For serum/plasma FSH: You may need to fast for 8–12 hours before the draw, but this is not always required. For 24-hour urine FSH: Collect all urine over 24 hours, starting after your first morning urine. Follow your lab’s specific instructions to ensure accuracy.

How the Test Works

Blood or urine samples are taken and analyzed using an immunoassay method to detect FSH levels. The test measures the hormone’s concentration in your blood or urine, depending on the protocol.

What the Results Mean

Results are compared to standard ranges for your age and sex. High or low FSH levels can signal potential issues with hormone production, reproductive health, or other underlying 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.

◆Associated findings1

Short name

FSH Level

Frequently asked questions

What causes FSH levels to be too high?
High FSH levels can result from conditions like premature ovarian insufficiency, ovarian cysts, or certain genetic disorders. It may also appear in men with low testosterone or pituitary tumors.
What causes FSH levels to be too low?
Low FSH can be linked to pituitary disorders, thyroid issues, or conditions affecting hormone regulation. Rarely, it may occur in men with Klinefelter syndrome or other genetic factors.
How often should I get an FSH test?
Your doctor will determine the frequency based on your symptoms, medical history, or treatment needs. Regular monitoring may be recommended if you have known reproductive 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