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Luteinizing Hormone (LH) in Serum or Plasma

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

This blood test measures the levels 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
47688-7
Short code
LH pre 100 ug LRH IV SerPl-aCnc
Synonyms
LH 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?

Doctors may order an LH test to diagnose or monitor conditions affecting hormone levels, such as infertility, menstrual irregularities, or pituitary gland disorders. It can also be used to check for conditions like polycystic ovary syndrome (PCOS) or to evaluate hormonal imbalances in both men and women.

What to Expect Before the Test

No special preparation is usually needed, but your doctor may advise fasting or avoiding certain medications. For women, timing can be important—some tests may be done during specific phases of the menstrual cycle.

How the Test Works

A blood sample is taken from a vein, typically in your arm. The sample is then sent to a lab where it is analyzed to measure LH levels using an immunoassay method, which detects the hormone in your blood.

Possible Results and Interpretation

Results are compared to a reference range that varies by age, sex, and reproductive status. Elevated or low LH levels may indicate underlying health concerns that require further evaluation by a 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 Test

Frequently asked questions

What Does an Abnormal LH Level Mean?
High LH levels may suggest conditions like premature ovarian insufficiency in women, hyperprolactinemia, or certain tumors affecting hormone production. In men, elevated LH can indicate hypogonadism or other pituitary disorders. Low LH levels may point to conditions like hypogonadotropic hypogonadism, Kallmann syndrome, or pituitary tumors.
How Often Should I Get This Test?
The frequency depends on your medical condition and treatment plan. Your doctor will determine how often to repeat the test based on your individual needs, such as monitoring fertility treatments, managing hormonal disorders, or assessing symptoms.
Can Diet or Lifestyle Affect LH Levels?
While diet and lifestyle factors like stress, weight, and exercise can influence overall hormone balance, they do not directly alter LH levels in the same way as medical conditions or medications. Always follow your doctor’s advice regarding lifestyle adjustments related to your specific health goals.
  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