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Luteinizing Hormone (LH) in Serum/Plasma

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

This test measures the amount of luteinizing hormone, a hormone produced by the pituitary gland, in your blood. It helps assess reproductive health and hormone balance.

Quick summary

["LH levels can indicate issues with ovulation, fertility, or hormonal imbalances."]

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

Key facts at a glance

LOINC
48118-4
Short code
LH 15M pre 100 ug LRH IV SerPl-aCnc
Synonyms
LH 15M pre 100 ug LRH IV SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
1.5
Ref high
9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83002
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 LH test to evaluate fertility, diagnose conditions like polycystic ovary syndrome (PCOS), check for hormonal imbalances, or monitor treatment for hormone-related disorders. It’s often part of a broader evaluation for irregular menstrual cycles or unexplained infertility.

What to Expect Before the Test

No special preparation is usually needed, but your doctor might advise timing the test around your menstrual cycle (e.g., mid-cycle for fertility assessment). Avoid smoking or strenuous activity 24 hours before the test if instructed.

How the Test Is Performed

A blood sample is drawn from a vein, typically in your arm. The sample is sent to a lab for analysis using an immunoassay method to detect LH levels.

What the Results Mean

Results are compared to a general reference range, but individual ranges may vary. High LH levels might suggest conditions like premature ovarian insufficiency or PCOS, while low levels could indicate hypothyroidism or pituitary disorders. Always discuss results with your healthcare provider.

Reference range

Follicular: 1.5-9.0 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

Short name

LH Level

Frequently asked questions

What Are Common Causes of Abnormal Results?
High LH levels may be linked to conditions like ovarian dysfunction, certain tumors, or stress-related hormonal shifts. Low LH levels could result from pituitary tumors, thyroid disorders, or genetic factors affecting hormone production.
How Often Should I Get This Test?
Your doctor will determine the frequency based on your symptoms, medical history, and treatment plan. Follow-up tests may be scheduled if you’re undergoing fertility treatment or managing a known hormonal condition.
Can Diet or Lifestyle Affect LH Levels?
While diet and exercise can influence overall hormone health, LH levels are primarily regulated by the brain and pituitary gland. Avoiding extreme stress, maintaining a balanced diet, and staying hydrated may support overall hormonal balance, but they don’t directly alter LH test 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