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Serum/Plasma Free Progesterone Concentration

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

This test measures the amount of free (unbound) progesterone in your blood, an important hormone involved in reproductive health and pregnancy.

Quick summary

["Progesterone helps regulate menstrual cycles and supports early pregnancy."]

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

Key facts at a glance

LOINC
34064-6
Short code
GH pre/p Ins SerPl-mCnc
Synonyms
GH pre/p Ins SerPl-mCnc
Category
hormone
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 This Test Might Be Ordered

Your healthcare provider may recommend this test to evaluate hormone balance, diagnose fertility issues, assess ovulation, or monitor conditions like polycystic ovary syndrome (PCOS) or pregnancy complications. It can also help track hormone levels during fertility treatments or hormone therapy.

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 blood draw if your test involves fasting-related measurements. Wear comfortable clothing and plan to rest for a few minutes afterward.

What Happens During the Test

A healthcare professional will insert a small needle into a vein in your arm to draw blood. You may feel a brief pinch, but it’s typically over quickly. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results help determine whether your progesterone levels are within expected ranges for your cycle phase, pregnancy status, or medical condition. Abnormal levels may indicate issues like hormonal imbalances, ovulation problems, or other reproductive health concerns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Progesterone

Frequently asked questions

How often should I get this test?
The frequency depends on your medical needs. For fertility or pregnancy monitoring, your provider may order it monthly or at specific cycle phases. If you have a chronic condition like PCOS, they might recommend it periodically to track hormone trends.
What are typical reference ranges?
Reference ranges vary by lab and cycle phase. For non-pregnant women, free progesterone levels typically fall between 0.3–20 ng/dL during the luteal phase (after ovulation). Pregnant women may have higher levels, but exact ranges depend on trimester. Your results will be compared to your specific lab’s standards.
Can lifestyle changes affect my progesterone levels?
Yes, stress, poor sleep, excessive exercise, and certain medications (like birth control or antidepressants) can influence progesterone. Avoiding alcohol and maintaining a balanced diet may help support natural hormone regulation. Always discuss lifestyle adjustments with your provider.
  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