Free (unbound) progesterone in serum/plasma
This test measures the amount of progesterone that is not attached to proteins in your blood, which can help assess hormone balance, especially in reproductive health.
["Free progesterone levels help diagnose hormonal imbalances and support fertility planning."]
Key facts at a glance
- LOINC
- 72889-9
- Short code
- Progest Free SerPl-mCnc
- Synonyms
- Progest Free SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 this test to evaluate hormone function, diagnose conditions like polycystic ovary syndrome (PCOS), or monitor treatment for hormonal disorders. It’s also used in fertility planning to check progesterone levels at different stages of the menstrual cycle or pregnancy.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if instructed. Wear comfortable clothing and plan to rest after the test. Avoid smoking or caffeine before the draw if your provider advises it.
What Happens During the Test?
A healthcare professional will collect a small sample of blood from a vein in your arm. The process is quick and usually painless. The blood will be sent to a lab for analysis using a sensitive immunoassay method to measure free progesterone levels accurately.
What Do Results Mean?
Results are interpreted based on your cycle phase, medical history, and symptoms. High or low free progesterone levels may indicate issues like ovulation problems, hormonal imbalances, or pregnancy complications. Your provider will discuss findings with you in the context of your overall health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free progesterone is critical for regulating the menstrual cycle, supporting pregnancy, and maintaining reproductive health. Low levels may signal ovulation disorders, while elevated levels could indicate conditions like hyperandrogenism or certain tumors. It’s particularly useful in fertility evaluations and managing hormonal therapies.
Short name
Free Progesterone
Frequently asked questions
What causes free progesterone levels to be tested?
How long does it take to get results?
Can lifestyle changes affect free progesterone 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