Luteinizing Hormone (LH) in Serum or Plasma
This blood 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.
["LH helps regulate important reproductive processes and may be checked if you have symptoms or concerns related to fertility or hormonal imbalances."]
Key facts at a glance
- LOINC
- 25718-8
- Short code
- LH 1h p 100 ug LRH IV SerPl-aCnc
- Synonyms
- LH 1h 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
Why Is This Test Done?
Your healthcare provider may order an LH test to evaluate reproductive function, diagnose conditions like polycystic ovary syndrome (PCOS), assess infertility, or monitor hormonal treatments. It can also help check for pituitary gland issues or hormonal imbalances that may affect other body systems.
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 your blood is drawn early in the morning. Wear comfortable clothing and plan to rest after the draw. If you’re taking medications that affect LH levels, let your provider know.
What Happens During the Test?
A healthcare professional will collect a small blood sample from a vein in your arm using a needle. The sample is then sent to a lab for analysis. The process takes about 15 minutes total, and you may feel slight discomfort but no lasting effects.
What Are Possible Results?
Results are typically reported in international units per liter (IU/L). Your provider will interpret the results in relation to your age, sex, and overall health. Abnormal results may trigger further testing or evaluation of underlying conditions.
Reference range
Follicular: 1.5-9.0 mIU/mLN/A
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.
High LH levels may indicate conditions like premature ovarian insufficiency, PCOS, or pituitary tumors. Low LH levels could suggest hypothyroidism, pituitary disorders, or other hormonal deficiencies. LH is also monitored during fertility treatments to track ovulation or sperm production.
Short name
LH Test
Frequently asked questions
How often should LH levels be checked?
What does an LH test measure exactly?
Can lifestyle factors affect LH levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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