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Luteinizing Hormone (LH) – Serum Immunoassay

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

This test measures the amount of luteinizing hormone (LH) in your blood. LH is a hormone produced by the pituitary gland that plays a key role in reproductive health, including ovulation in women and sperm production in men.

Quick summary

["LH helps regulate important reproductive processes and may be checked for fertility or hormonal imbalances."]

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

Key facts at a glance

LOINC
57105-9
Short code
LH 30M p GnRH SerPl-aCnc
Synonyms
LH 30M p GnRH 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 Does LH Measure?

LH is part of the hormonal system that triggers ovulation in women and stimulates testosterone production in men. It fluctuates throughout the menstrual cycle and responds to changes in other hormones like follicle-stimulating hormone (FSH).

Why Might You Need This Test?

Doctors may order an LH test to diagnose fertility issues, evaluate hormonal imbalances, check for conditions like polycystic ovary syndrome (PCOS), or monitor treatment for hormone-related disorders.

Sample Collection and Preparation

A blood sample is taken 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 for analysis using an immunoassay method to detect LH levels.

What to Expect Before or After the Test

You may experience mild discomfort or bruising at the injection site, but this usually fades quickly. Avoid strenuous activity for a short time after the blood draw. Results are typically ready within a few days.

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.

◆Associated findings1

Short name

LH Test

Frequently asked questions

How often should I get an LH test?
The frequency depends on your medical needs. Your doctor will determine if regular monitoring is required, such as during fertility treatments, hormone replacement therapy, or if you have symptoms of hormonal imbalances.
What do my LH test results mean?
Your results will be compared to standard reference ranges provided by your lab. While exact values vary by lab, very high or very low levels may signal underlying health concerns that your doctor will discuss with you.
Can lifestyle changes affect LH levels?
Yes, factors like stress, weight fluctuations, certain medications (e.g., birth control, antidepressants), and smoking can influence LH. Maintaining a healthy lifestyle and discussing medications with your doctor may help optimize 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