Hemoglobin (Hb) concentration in whole blood, measured by a standard automated method
This test measures the amount of hemoglobin in your blood, which carries oxygen from your lungs to the rest of your body. Hemoglobin levels help doctors assess your red blood cell health and overall blood health.
["Hemoglobin levels indicate whether you have enough oxygen-carrying capacity in your blood."]
Key facts at a glance
- LOINC
- 104879-2
- Short code
- Hct 2.5h p Glc VFr Bld
- Synonyms
- Hct 2.5h p Glc VFr Bld
- Category
- glucose
- 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
- true
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 test to check for anemia (low red blood cells), polycythemia (high red blood cells), or other blood-related conditions. It’s also used during pregnancy, before surgeries, or if you have symptoms like fatigue, dizziness, or shortness of breath.
What to Expect Before the Test
You’ll typically have a small needle inserted into your arm or hand to draw a blood sample. It usually takes a few minutes, and you may feel a slight pinch. No special preparation is needed unless your doctor instructs otherwise.
What the Results Mean
Results are compared to a general reference range for healthy adults, but your doctor will interpret them based on your specific health needs. Very low or very high levels can signal underlying health concerns.
Common Conditions Linked to Abnormal Results
Low hemoglobin may indicate anemia, blood loss, or iron deficiency. High levels could suggest dehydration, living at high altitudes, or certain blood disorders. Your doctor will discuss findings with you in detail.
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.
Hemoglobin is a critical marker for diagnosing and monitoring conditions like anemia, which can cause fatigue, weakness, or pale skin. It also helps assess blood health during pregnancy, cancer treatments, or chronic diseases like kidney disease. Persistently abnormal levels may prompt further testing to identify root causes.
Short name
Hb (Whole Blood)
Frequently asked questions
What does a low hemoglobin level mean?
How is hemoglobin tested?
Can diet affect hemoglobin levels?
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