Free hemoglobin concentration in urine (24-hour collection)
This test measures the amount of free hemoglobin (the protein part of red blood cells) that appears in your urine over a 24-hour period. Free hemoglobin can indicate conditions affecting red blood cells or blood breakdown.
["Helps detect hidden blood loss or red blood cell disorders by tracking free hemoglobin in urine."]
Key facts at a glance
- LOINC
- 99063-0
- Short code
- Free H2O Ur+SerPl-vRate
- Synonyms
- Free H2O Ur+SerPl-vRate
- 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 This Test Is Done
Your healthcare provider may order this test if you have symptoms like frequent fatigue, pale skin, or unexplained anemia. It can also be used to monitor conditions such as hemolytic anemia (where red blood cells break down too quickly) or blood loss from the gastrointestinal tract.
What to Expect Before the Test
You’ll collect all urine for 24 hours in a special container. Drink plenty of fluids to ensure full collection. Avoid certain medications or supplements that might affect results, as directed by your provider.
How the Test Works
The collected urine is analyzed to measure free hemoglobin levels. This is typically done using a specialized laboratory method to differentiate free hemoglobin from other forms in urine.
Possible Results and Interpretation
Higher-than-normal levels may suggest conditions like hemolysis, blood in the urine (hematuria), or certain kidney diseases. Lower-than-normal levels may indicate dehydration or other factors reducing urine output.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated free hemoglobin in urine can signal red blood cell destruction (hemolysis), which may be due to conditions like sickle cell disease, autoimmune disorders, or infections. It can also indicate blood loss from the gastrointestinal tract or kidney issues. This test helps guide treatment for anemia or other blood-related disorders.
Short name
24-Hour Free Hemoglobin Urine Test
Frequently asked questions
What does a high free hemoglobin level in urine mean?
What causes low free hemoglobin in urine?
Can diet affect this test?
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