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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 (LH), a hormone produced by the pituitary gland that plays a key role in reproductive health.

Quick summary

["LH helps regulate ovulation in women and sperm production in men."]

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

Key facts at a glance

LOINC
25719-6
Short code
LH 2h p 100 ug LRH IV SerPl-aCnc
Synonyms
LH 2h p 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

What LH Measures

LH is crucial for triggering ovulation in women and stimulating testosterone production in men. It fluctuates throughout the menstrual cycle and responds to changes in other hormones, such as follicle-stimulating hormone (FSH).

Why It’s Tested

Doctors may order an LH test to evaluate fertility issues, monitor hormonal imbalances, diagnose conditions like polycystic ovary syndrome (PCOS), or check for pituitary gland problems. It can also be part of routine evaluations for hormonal disorders.

Sample Collection and Preparation

This test requires a blood sample drawn from a vein in your arm. You may need to fast for a few hours before the test, depending on your doctor’s instructions. The sample is sent to a lab where it is processed into either serum or plasma for analysis.

Test Process and Results

The lab uses an immunoassay method to detect LH in your sample. Results are typically reported in international units per liter (IU/L) or milliliters per liter (mIU/mL), though exact units may vary by lab. Your doctor will interpret the results in relation to your overall health and medical history.

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 Test

Frequently asked questions

How LH Levels Can Affect Health
Low LH levels may indicate pituitary gland disorders, hormonal deficiencies, or conditions like hypogonadism. High LH levels can suggest conditions like PCOS, ovarian dysfunction, or certain tumors. Always discuss any abnormal results with your healthcare provider.
When to Expect Results
You’ll usually receive your LH test results within a few days to a couple of weeks, depending on your lab and insurance. Your doctor will explain the results and next steps during your follow-up visit.
What to Expect During the Test
You may feel slight discomfort or bruising at the injection site, but the procedure itself is quick and painless. Avoid strenuous activity for a few hours afterward to prevent bleeding at the site.
  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