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Luteinizing Hormone (LH) in Serum or Plasma

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

This test measures the amount of luteinizing hormone, a hormone produced by the pituitary gland that plays a key role in reproductive health.

Quick summary

["LH helps regulate menstrual cycles and sperm production."]

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

Key facts at a glance

LOINC
15292-6
Short code
Height Testis-L US.meas
Synonyms
Height Testis-L US.meas
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-measured
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 Might Be Ordered

Your doctor may recommend an LH test to evaluate fertility issues, monitor hormonal imbalances, or assess conditions like polycystic ovary syndrome (PCOS) or pituitary disorders. It can also be part of routine evaluations for irregular menstrual cycles or unexplained infertility.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours if the test involves drawing blood from a vein. If you’re taking medications that affect hormones, inform your healthcare provider beforehand.

How the Test Works

A small sample of blood (serum or plasma) is drawn from a vein in your arm. The sample is then analyzed in a lab using an immunoassay method to detect and measure LH levels.

What the Results Mean

Results are typically reported in international units per liter (IU/L). Higher-than-normal levels may indicate conditions like early puberty, tumors affecting the pituitary gland, or certain thyroid disorders. Lower-than-normal levels could suggest issues with the pituitary or hypothalamus.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

LH Level

Frequently asked questions

What Does LH Measure?
LH triggers ovulation in women and stimulates testosterone production in men. Abnormal LH levels can signal underlying hormonal imbalances that may require further medical evaluation, such as hormone replacement therapy or targeted treatments for fertility or reproductive health.
How Often Should I Get This Test?
The frequency depends on your symptoms and medical history. Your doctor may recommend periodic testing if you have conditions like PCOS, menopause symptoms, or unexplained infertility. Follow-up tests are often scheduled every 6–12 months.
Can Diet or Exercise Affect LH Levels?
Yes, lifestyle factors like stress, weight fluctuations, and certain medications (e.g., birth control, antidepressants) can influence LH levels. Maintaining a healthy weight, managing stress, and avoiding smoking may help stabilize hormone balance.
  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