Luteinizing Hormone (LH) – Serum Immunoassay
This test measures the amount of luteinizing hormone 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 your menstrual cycle and fertility."]
Key facts at a glance
- LOINC
- 46414-9
- Short code
- LH 15M p GnRH SerPl-aCnc
- Synonyms
- LH 15M 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 LH Measures
LH is primarily involved in triggering ovulation in women and stimulating testosterone production in men. It also helps regulate the menstrual cycle and reproductive hormones. Your body releases LH in pulses, and its levels can vary throughout the menstrual cycle or at different stages of life.
Why It’s Ordered
Doctors may order LH testing to evaluate fertility issues, menstrual irregularities, or hormonal imbalances. It can also be used to monitor conditions like polycystic ovary syndrome (PCOS), pituitary disorders, or to check for signs of early menopause.
Sample Collection and Preparation
This test requires a blood sample drawn from a vein in your arm. You may need to fast for 8–12 hours before the test, depending on the clinic’s instructions. Avoid strenuous activity or smoking before the draw to ensure accurate results.
What to Expect During the Test
The blood sample is taken by a healthcare professional using a small needle. You may feel a slight pinch, but it usually doesn’t cause significant discomfort. The sample is then sent to a lab for analysis using an immunoassay method to detect LH levels precisely.
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.
◆Associated findings1
Short name
LH Level
Frequently asked questions
High LH levels may indicate conditions like early menopause, pituitary tumors, or hormonal imbalances affecting fertility. Low LH levels could suggest hypothyroidism, pituitary disorders, or other conditions that disrupt normal hormone production.
How long does it take to get results? Results from an LH blood test are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once the results are ready.
Is fasting required for this test? Fasting guidelines may vary, but many labs recommend avoiding food for 8–12 hours before the test. Always follow your healthcare provider’s specific instructions for the best accuracy.
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