High Molecular Weight Glycated Hemoglobin (HMW-HbA₂)
This test measures specific glycated hemoglobin variants, including high-molecular-weight forms, which may reflect chronic blood sugar exposure in certain conditions.
["This test helps assess blood sugar control in conditions where standard hemoglobin A1c may not be fully representative."]
Key facts at a glance
- LOINC
- 34660-1
- Short code
- Hgb A2 MFr Bld Column Chrom
- Synonyms
- Hgb A2 MFr Bld Column Chrom
- 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
- chromatography-column
- 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 recommend this test if you have diabetes or prediabetes, or if you experience symptoms like fatigue, frequent infections, or unusual bleeding that traditional hemoglobin A1c does not explain. It may also be used in research or specialized clinical settings to study hemoglobin variants.
How the Test Works
A small blood sample is collected and analyzed to detect these specific glycated hemoglobin forms, which can indicate prolonged exposure to high blood sugar levels.
What to Expect Before the Test
No special preparation is needed for this test. You may have a standard blood draw, similar to other lab tests. If you are on blood thinners, let your provider know before the test.
What the Results Mean
Higher levels of HMW-HbA₂ variants may suggest conditions like thalassemia or other hemoglobinopathies, where abnormal hemoglobin production occurs, or in certain metabolic disorders.
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.
Clinical Significance
Short name
HMW-HbA₂ Profile
Frequently asked questions
What does a high or low result mean?
Does this test replace standard hemoglobin A1c?
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