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FSH (Follicle Stimulating Hormone) – Serum/plasma concentration

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

This test measures the amount of follicle-stimulating hormone (FSH) in your blood. FSH plays a key role in regulating reproductive hormones and supporting egg development in women and sperm production in men.

Quick summary

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

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

Key facts at a glance

LOINC
14291-9
Short code
FSH BS SerPl-sCnc
Synonyms
FSH BS 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

Why Is This Test Done?

Your doctor may order an FSH test to check for hormonal imbalances, evaluate fertility issues, diagnose conditions like early menopause or polycystic ovary syndrome (PCOS) in women, or assess hormonal health in men. It can also help monitor conditions like hypogonadism or pituitary disorders.

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 requires it, but this depends on the specific testing protocol. Bring any medications you’re currently taking to your appointment.

What Happens During the Test?

A healthcare provider will insert a small needle into a vein in your arm or hand to collect blood. 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 Are Possible Results?

Results are interpreted based on your age, gender, and overall health. High or low FSH levels can signal underlying medical conditions, but they’re not standalone diagnoses. Your doctor will discuss findings in relation to 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.

◆Associated findings1

Short name

FSH Level

Frequently asked questions

What Does an Elevated FSH Level Mean?
Elevated FSH levels may indicate early menopause, ovarian dysfunction, or conditions like PCOS in women. In men, it could signal low testosterone or pituitary issues. Your doctor will consider other factors, such as age and symptoms, before making a diagnosis.
What Does a Low FSH Level Mean?
Low FSH levels might suggest hypogonadism (underactive ovaries/testes), pituitary tumors, or other hormonal imbalances. In women, it could be linked to conditions like Turner syndrome. Further testing may be needed to explore the cause.
How Often Should I Get This Test?
FSH testing frequency depends on your symptoms and medical needs. For fertility evaluation, it may be done multiple times. If monitoring a chronic condition, your doctor will determine how often retests are needed.
  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