Reference range 1
>= 13 – <= 18 g/dL
- Population
- Adults
- Sex
- Male
- Specimen
- Whole blood
Example reference interval
MedlinePlus example reference interval; WHO clinical anaemia cutoffs are separate records.
Information about a laboratory test
Low Hemoglobin (HGB): What Does It Mean?
A result below the reference range may be seen with anemia. Possible causes are not limited to iron deficiency and can include blood loss, chronic disease, vitamin deficiencies, or bone-marrow disorders.
Test summary
- Test name
- Hemoglobin (HGB)
- Abbreviations
- HGB, Hb
- Category
- Hematology
- Panel
- Complete Blood Count (CBC) / Hemogram
- Specimen
- Whole blood
- Common units
- g/dL, g/L
What does the test measure?
Measures the amount of hemoglobin, the oxygen-carrying protein inside red blood cells, in the blood.
Why is the test ordered?
Used as part of the complete blood count to assess anemia, increased red-cell mass, and general blood health.
Information about a low result
A result below the reference range may be seen with anemia. Possible causes are not limited to iron deficiency and can include blood loss, chronic disease, vitamin deficiencies, or bone-marrow disorders.
Information about a high result
A result above the reference range may occur with dehydration, long-term low oxygen levels, high altitude, smoking, or conditions that increase red blood cell production.
Reference and clinical context
Use the reference interval printed on your own laboratory report first. Reference intervals may vary by laboratory, method, unit, age, sex, pregnancy, specimen, and other conditions. Numeric records in this workbook are explicitly labeled as either source-based example reference intervals or clinical decision cutoffs.
Reference range 2
>= 12 – <= 16 g/dL
- Population
- Adults
- Sex
- Female
- Specimen
- Whole blood
Example reference interval
MedlinePlus example reference interval; WHO clinical anaemia cutoffs are separate records.
Reference context 3
>= 105 g/L
- Population
- Children 6–23 months
- Age range
- 0.5 – 1.99
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 4
>= 110 g/L
- Population
- Children 24–59 months
- Age range
- 2 – 4.99
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 5
>= 115 g/L
- Population
- Children 5–11 years
- Age range
- 5 – 11.99
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 6
>= 120 g/L
- Population
- Children 12–14 years, nonpregnant girls
- Sex
- Female
- Age range
- 12 – 14.99
- Pregnancy status
- No
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 7
>= 120 g/L
- Population
- Children 12–14 years, boys
- Sex
- Male
- Age range
- 12 – 14.99
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 8
>= 120 g/L
- Population
- Adults 15–65 years, nonpregnant women
- Sex
- Female
- Age range
- 15 – 65
- Pregnancy status
- No
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 9
>= 130 g/L
- Population
- Adults 15–65 years, men
- Sex
- Male
- Age range
- 15 – 65
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 10
>= 110 g/L
- Population
- Pregnancy, first trimester
- Sex
- Female
- Pregnancy status
- Yes
- Trimester
- 1
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 11
>= 105 g/L
- Population
- Pregnancy, second trimester
- Sex
- Female
- Pregnancy status
- Yes
- Trimester
- 2
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference context 12
>= 110 g/L
- Population
- Pregnancy, third trimester
- Sex
- Female
- Pregnancy status
- Yes
- Trimester
- 3
- Specimen
- Venous blood
WHO 'no anaemia' lower boundary
Clinical anaemia classification cutoff from WHO 2024; not a laboratory reference interval. Altitude/smoking adjustments may apply.
Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.
Interpretation notes
Low hemoglobin is important for identifying anemia, but it does not show the cause of anemia. MCV, RDW, ferritin, reticulocytes, vitamin B12/folate, and the clinical history can help distinguish possible causes.
Related specialties
- Hematology
- Internal Medicine
- Pediatrics
- Obstetrics and Gynecology
Frequently asked questions
Sources
CBC blood test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · CBC components; example adult reference ranges; high/low RBC, WBC and platelet context · Verified: Aug 11, 2026
Red Blood Cell (RBC) Indices — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · MCV, MCH, MCHC, RDW definitions and interpretation · Verified: Aug 11, 2026
Hemoglobin Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Hemoglobin purpose and interpretation · Verified: Aug 11, 2026
RDW (Red Cell Distribution Width) — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · RDW interpretation; low RDW usually not concerning; combine with other indices · Verified: Aug 11, 2026
Reticulocyte Count — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Reticulocyte count and bone marrow response · Verified: Aug 11, 2026
Ferritin Blood Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2025 · Ferritin purpose; low/high context; inflammation and liver-related causes of elevation · Verified: Aug 11, 2026
Guideline on haemoglobin cutoffs to define anaemia in individuals and populations — World Health Organization
WHO guideline · 2024 · Age-, sex- and pregnancy-specific clinical haemoglobin cutoffs; not laboratory reference intervals · Verified: Aug 11, 2026
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