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Hemoglobin F (Fraction of Total Hemoglobin)

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

This test measures the percentage of fetal hemoglobin in your blood, which is naturally present in newborns but typically decreases as you age.

Quick summary

["HbF levels can offer insights into conditions affecting red blood cells or hemoglobin production."]

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

Key facts at a glance

LOINC
4632-6
Short code
Hgb F Bld Ql Alk Denat
Synonyms
Hgb F Bld Ql Alk Denat
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
Method
alkali-denat
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

Why This Test Might Be Ordered

Your healthcare provider may check your HbF percentage if you have symptoms like anemia, unexplained fatigue, or if they suspect conditions like thalassemia, sickle cell disease, or certain blood disorders. It may also be used in newborn screening or research studies.

What to Expect Before the Test

No special preparation is needed. A simple blood draw from your arm will be performed in a clinic or lab. The test is usually done on whole blood.

What the Results Mean

Results are expressed as a percentage of total hemoglobin. Higher-than-normal levels may indicate certain genetic blood disorders, while lower levels could suggest conditions affecting red blood cell production.

Common Conditions Influencing Results

Elevated HbF levels can be seen in conditions like beta-thalassemia, sickle cell disease, or certain cancers. Lower levels may be associated with polycythemia or other hemoglobinopathies.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: whole-blood

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.

Clinical Significance

Short name

HbF %

Frequently asked questions

What questions do you have about HbF testing?
HbF testing helps diagnose or monitor certain blood disorders. It can also be part of research or newborn screening programs to identify potential health issues early.
How is HbF tested?
HbF is tested through a simple blood draw. The blood is analyzed to determine the proportion of fetal hemoglobin among all hemoglobin types present in your red blood cells.
Can HbF levels change over time?
Yes, HbF levels can vary. In newborns, it naturally decreases as the body transitions to producing adult hemoglobin. Certain medical conditions may also cause fluctuations.
  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