Hemoglobin concentration (mass concentration in whole blood)
This test measures the amount of hemoglobin, the protein in red blood cells that carries oxygen throughout your body. It’s often checked to assess overall blood health.
["Hemoglobin levels help diagnose and monitor conditions like anemia or blood loss."]
Key facts at a glance
- LOINC
- 40720-5
- Short code
- Hgb C Bld Ql
- Synonyms
- Hgb C Bld Ql
- 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
- 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 Is This Test Done?
Your healthcare provider may order this test to check for anemia (low hemoglobin), detect blood disorders, evaluate iron deficiency, or monitor conditions like chronic kidney disease or heart disease. It can also be part of routine blood work or during pregnancy to ensure healthy fetal development.
What to Expect Before the Test
No special preparation is needed, but you may fast for 8–12 hours before the test if it’s part of a fasting blood panel. Wear comfortable clothing and avoid heavy exercise. Tell your provider about any medications or supplements you take, as they may affect results.
What Happens During the Test
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but it usually doesn’t cause significant discomfort. The process takes just a few minutes, and you can resume normal activities afterward.
What the Results Mean
Results are compared to standard ranges for your age, sex, and overall health. Low hemoglobin may indicate anemia or blood loss, while very high levels could signal conditions like polycythemia. Your provider will discuss findings in the context of your symptoms and medical history.
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.
Hemoglobin levels are critical for diagnosing anemia (a condition where your body lacks enough healthy red blood cells to carry oxygen), identifying blood loss (e.g., from ulcers, heavy periods, or trauma), or detecting underlying issues like kidney disease or liver problems. Chronic low levels may also signal nutritional deficiencies (e.g., iron, vitamin B12, or folate). Elevated levels could suggest polycythemia (overproduction of red blood cells) or dehydration. Regular monitoring helps manage conditions like heart disease or pregnancy-related changes.
Short name
Hemoglobin (Hgb)
Frequently asked questions
How often should I get this test?
Can diet affect my hemoglobin test results?
What if my hemoglobin is outside the normal range?
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