Hemoglobin (Hb) and Hematocrit (Hct) with Denaturation Heat Test
This test measures hemoglobin and hematocrit levels in your blood and evaluates how these levels change when exposed to heat, which can help assess red blood cell stability and potential conditions like hemolysis or hemoglobinopathies.
["This test helps identify issues with red blood cells that may affect their ability to carry oxygen safely under stress or heat exposure."]
Key facts at a glance
- LOINC
- 17871-5
- Short code
- Hgb H Bld Ql Heat Denat
- Synonyms
- Hgb H Bld Ql Heat 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
- heat-denaturation
- 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 This Test Measures
The test initially measures your baseline hemoglobin (Hb) and hematocrit (Hct) levels, which reflect the amount of oxygen-carrying protein and red blood cell volume in your blood. It then exposes a sample of your blood to heat to observe changes in these levels, indicating how heat-sensitive your red blood cells are.
Why It Matters in Your Blood
Hemoglobin and hematocrit are critical for transporting oxygen throughout your body. Heat-induced changes can reveal whether your red blood cells are fragile or prone to breaking down, which may signal underlying conditions like hereditary spherocytosis, sickle cell trait, or other hemoglobin disorders.
Common Conditions Evaluated
This test is often used to diagnose or monitor conditions where red blood cells are unstable, such as hereditary hemolytic anemias or certain genetic hemoglobin disorders. It may also be part of a broader evaluation for unexplained anemia or symptoms like fatigue, weakness, or jaundice.
Sample Collection and Preparation
A blood sample is drawn from a vein, typically in your arm. The sample is processed to separate plasma from red blood cells and then analyzed under normal and heat-treated conditions to measure hemoglobin and hematocrit levels.
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A
For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Hb/Hct Denaturation Profile
Frequently asked questions
Why might my doctor order this test?
What do abnormal results 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