Calculated Hematocrit from Red Blood Cell Count and Hemoglobin Concentration
Your blood test may measure this value indirectly by calculating it from other blood components, such as red blood cell count and hemoglobin levels. This helps assess your red blood cell volume in relation to your blood plasma.
["This calculated measure helps doctors evaluate red blood cell health and potential blood disorders."]
Key facts at a glance
- LOINC
- 71831-2
- Short code
- Hct VFr.DF BldC Calc
- Synonyms
- Hct VFr.DF BldC Calc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 36
- Ref high
- 50
- Critical range
- 18 N/A – 60 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- calculated
- CPT
- 85014
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this calculation when they suspect conditions like anemia, polycythemia, or dehydration. It can also be used to monitor chronic diseases or after treatments that affect red blood cells.
What to Expect Before the Test
No special preparation is needed. You’ll have a simple blood draw from a vein, usually in your arm. The process takes a few minutes, and you may feel slight discomfort, but it’s generally well-tolerated.
What the Results Mean
Hematocrit is calculated as the ratio of red blood cells to total blood volume. While this test doesn’t provide a standalone result, it’s used alongside other blood measurements to diagnose or monitor conditions affecting red blood cells.
Common Conditions Monitored
This calculation is often used in conjunction with hemoglobin and red blood cell counts to identify or track conditions like iron deficiency, kidney disease, or blood disorders such as sickle cell anemia.
Reference range
Adult males: 38-50%; Females: 36-44%N/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: Hematocrit is a key indicator of red blood cell health and overall blood volume. Low levels may signal anemia or fluid loss, while high levels could indicate polycythemia or dehydration. Doctors use this alongside other blood tests to guide treatment decisions.
Short name
Hct Calc
Frequently asked questions
What does a calculated hematocrit tell me about my health?
How is this test different from a standard hematocrit test?
Can I affect my hematocrit calculation results?
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 17, 2026. · Read our editorial policy