Follicle-Stimulating Hormone to Creatinine Ratio, 24-Hour Urine
Measures follicle-stimulating hormone (FSH) relative to creatinine in urine collected for 24 hours. It may help assess hormone activity in fertility or reproductive evaluations.
["This test measures FSH relative to creatinine in a 24-hour urine collection."]
Key facts at a glance
- LOINC
- 29155-9
- Short code
- FSH/Creat 24h Ur-Rto
- Synonyms
- FSH/Creat 24h Ur-Rto
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 3.5
- Ref high
- 12.5
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 83001
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test measures follicle-stimulating hormone (FSH), a pituitary hormone that helps regulate ovulation and sperm production, in urine collected over 24 hours. The result may be expressed as a ratio to urinary creatinine, which helps account for differences in urine concentration.
Why might I need this test?
A clinician may order this test as part of an evaluation of fertility, menstrual changes, or reproductive function. FSH levels can vary during the menstrual cycle and with age, so the result is interpreted alongside medical history and other fertility tests.
How is the test performed?
You collect all urine produced during a full 24-hour period in the container provided by the laboratory. The laboratory then measures FSH and creatinine and may calculate their ratio.
How do I prepare for the test?
Follow the laboratory's collection instructions carefully, including the starting and ending times. Do not include urine collected before the collection period, and ask the laboratory whether the container should be refrigerated during the 24 hours.
Reference range
Follicular: 3.5-12.5 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.
An FSH result that is higher than expected may suggest reduced ovarian reserve or primary ovarian insufficiency, depending on the clinical context. A lower result can occur with normal reproductive function, hormonal contraception, or other conditions that suppress pituitary signaling. The 24-hour urine FSH-to-creatinine ratio must be interpreted by a clinician because urinary hormone levels vary with collection completeness, urine concentration, medications, and reproductive status.
Short name
24-Hour Urine FSH/Creatinine Ratio
Frequently asked questions
Is this the same as a blood FSH test?
Why is a 24-hour urine collection needed?
Can medications affect the result?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy