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

Quick summary

["LH helps regulate ovulation and sperm production."]

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

Key facts at a glance

LOINC
32995-3
Short code
LH 20M p chal SerPl-aCnc
Synonyms
LH 20M p chal 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 This Test Might Be Ordered

Your doctor may recommend an LH test to evaluate fertility issues, monitor hormonal imbalances, or check for conditions like polycystic ovary syndrome (PCOS), pituitary disorders, or menopause-related changes. It can also be part of routine testing for certain reproductive health evaluations.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s drawn in the morning. Avoid strenuous activity or excessive stress on the day of testing. If you’re on hormonal medications (like birth control), let your doctor know as it may affect results.

What Happens During the Test

A healthcare provider will collect a blood sample from a vein in your arm using a small needle. You may feel a brief pinch, but it’s usually over quickly. The sample is then sent to a lab for analysis.

What the Results Mean

Hormone levels can vary based on your menstrual cycle, age, and overall health. Your doctor will interpret the results in the context of your medical history and other tests. High or low LH levels may signal underlying conditions requiring further evaluation.

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

What Does an Abnormal LH Level Indicate?
Elevated LH levels might suggest conditions like premature ovarian insufficiency, PCOS, or pituitary tumors. Low LH could indicate hypothyroidism, pituitary disorders, or other hormonal deficiencies. Always discuss results with your healthcare provider.
How Often Should I Get This Test?
The frequency depends on your health goals. If you’re monitoring fertility, your doctor may recommend testing every few months. For routine checks, it’s often done once or twice a year if needed.
Can Diet or Lifestyle Affect LH Levels?
Yes! Stress, poor sleep, excessive exercise, and certain medications (like birth control) can influence LH. Maintaining a balanced diet, managing stress, and getting adequate rest may help support normal hormone function.
  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