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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 (FSH) in your blood. FSH helps regulate the production of eggs in women and sperm in men.

Quick summary

["FSH helps balance reproductive hormones and supports fertility."]

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

Key facts at a glance

LOINC
12667-2
Short code
FSH sp5 p chal SerPl-sCnc
Synonyms
FSH sp5 p chal SerPl-sCnc
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 testing is commonly used to evaluate reproductive health, diagnose fertility issues, and check for hormonal imbalances. In women, it helps assess ovulation, egg quality, and conditions like polycystic ovary syndrome (PCOS). In men, it may be checked for low sperm production or hormonal disorders.

Who Might Need This Test?

Your doctor may recommend an FSH test if you have symptoms like irregular periods (women), low libido or infertility (both genders), or if you’re investigating unexplained infertility or hormonal imbalances.

How Is the Test Done?

A blood sample is taken from a vein in your arm. You’ll typically fast for 8–12 hours before the test, but your doctor will explain exact instructions. The sample is sent to a lab for analysis.

What Are Common Results?

Results are compared to a general range for your gender and age, but individual results can vary. High or low FSH levels may signal 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.

◆Associated findings1

Short name

FSH Level

Frequently asked questions

Why might my FSH test be done on an empty stomach?
Fasting ensures more accurate results by reducing potential interference from food. Your doctor may recommend fasting to avoid fluctuations in hormone levels.
How long does it take to get my FSH results?
Results are usually available within 1–3 business days, depending on your lab’s processing time. Follow-up with your doctor to discuss findings.
Can lifestyle factors affect FSH levels?
Yes, stress, weight changes, and certain medications can influence hormone levels. If you suspect lifestyle factors are at play, talk to your doctor about adjustments.
  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