Hemoglobin F mass fraction (percent) in whole blood
This test measures the percentage of fetal hemoglobin (HbF) in your blood. HbF is a type of hemoglobin found in newborns that gradually decreases as a child matures.
["HbF levels can help diagnose or monitor certain blood conditions."]
Key facts at a glance
- LOINC
- 71857-7
- Short code
- Hgb S MFr.DF Bld
- Synonyms
- Hgb S MFr.DF Bld
- Category
- hematology
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- 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
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What Is Hemoglobin F?
Hemoglobin F (HbF) is a form of hemoglobin that carries oxygen in your blood. Unlike adult hemoglobin (HbA), HbF is primarily present in newborns and infants. As you grow older, your body produces less HbF and more HbA. This test specifically looks at the proportion of HbF in your blood.
Why Might You Need This Test?
Your healthcare provider may order this test if you have symptoms or risk factors for conditions like thalassemia, sickle cell disease, or other blood disorders. It can also be used during pregnancy to monitor fetal development or in newborns for early detection of genetic blood disorders.
Sample and Testing Process
A small blood sample is taken from a vein in your arm. The blood is then analyzed to determine the percentage of HbF. This test is usually done using a specialized laboratory technique to measure the mass fraction of HbF in whole blood.
What Are Normal Results?
There are no standard reference ranges provided here since they can vary by lab and patient age. Your results will be compared to what is typical for your age and health status.
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
Hemoglobin F %
Frequently asked questions
What causes abnormal HbF levels?
How often should I get this test?
Can lifestyle changes affect HbF 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