Skip to content

Hemoglobin F (HbF) Percentage in Whole Blood

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

This test measures the proportion of fetal hemoglobin (HbF) in your red blood cells. HbF is a type of hemoglobin present in newborns and some adults with certain blood disorders.

Quick summary

["HbF levels can help diagnose or monitor conditions like thalassemia or sickle cell disease."]

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

Key facts at a glance

LOINC
56490-6
Short code
Hgb sp2 Stl gastro lower Ql IA
Synonyms
Hgb sp2 Stl gastro lower Ql IA
Category
hematology
Sample
stool
Container
Clean container
Units
N/A
Ref low
10
Ref high
40
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
CPT
84484
SNOMED
302774002
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of blood disorders, such as fatigue, anemia, or unusual blood test results. It’s also used to monitor conditions like beta-thalassemia or sickle cell trait/disease, especially in newborns or those with a family history of these conditions.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw a small amount of blood, similar to other blood tests. The process is quick and usually painless.

What the Results Mean

Results show the percentage of HbF in your blood. Higher levels may indicate conditions like thalassemia or certain cancers (e.g., myeloproliferative disorders). Lower levels are typical in adults without these conditions.

Common Conditions Monitored

This test helps diagnose or track conditions like thalassemia (a genetic blood disorder), sickle cell disease, or fetal hemoglobin-related disorders. It may also be used in research or to assess blood cancers.

Reference range

Adult: 10-40 U/LN/A

Specimen: stool

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: HbF plays a protective role in sickle cell disease by reducing the formation of sickle-shaped red blood cells. Elevated HbF can sometimes mask anemia or other symptoms, so results are interpreted in the context of your overall health and symptoms.

Short name

HbF %

Frequently asked questions

What causes abnormal HbF levels?
Abnormally high HbF levels may be seen in conditions like beta-thalassemia, polycythemia vera, or certain cancers. Low levels are common in adults without blood disorders but can be checked if symptoms suggest an underlying issue.
How often should I get this test?
Frequency depends on your medical condition. If you have a diagnosed blood disorder, your doctor may recommend regular monitoring. Otherwise, this test is rarely routine unless symptoms arise or family history suggests risk.
Can diet or lifestyle affect HbF levels?
Diet and lifestyle generally do not directly influence HbF levels, as they are primarily determined by genetic factors or underlying blood disorders. Focus on managing symptoms and following your doctor’s advice for treatment.
  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