Urinary free hemoglobin mass concentration
This test measures the amount of free hemoglobin (a protein in red blood cells) that appears in your urine, separate from other blood components. It helps detect conditions where red blood cells break down or leak into urine.
["Assesses hidden blood loss or hemolysis in your body."]
Key facts at a glance
- LOINC
- 4636-7
- Short code
- Hgb Free Ur-mCnc
- Synonyms
- Hgb Free Ur-mCnc
- Category
- hematology
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 12
- Ref high
- 17.5
- Critical range
- 7 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85018
- SNOMED
- 900000000000003004
- 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
Why This Test Is Done
Your healthcare provider may order this test if you have symptoms like dark urine, fatigue, or signs of anemia. It can also be used to monitor conditions such as hemolytic anemia, blood disorders, or kidney issues where hemoglobin might appear in urine unexpectedly.
What to Expect Before the Test
No special preparation is needed. You’ll provide a urine sample, typically collected in the morning. Avoid strenuous activity or certain medications (like NSAIDs) that might affect results, but always follow your provider’s instructions.
How the Test Works
The test measures hemoglobin’s mass in your urine using a specialized laboratory method. Free hemoglobin can indicate red blood cell breakdown or abnormal leakage into urine, which isn’t detected by standard urine tests.
Possible Results and Interpretation
Results are compared to a reference range for your age and health status. Elevated levels may suggest conditions like hemolysis, blood disorders, or kidney problems. Low or normal levels don’t rule out these conditions, so results should be reviewed by your provider.
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Free Hemoglobin in Urine
Frequently asked questions
What does a high result mean?
What does a low result mean?
How often should I get 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