Hemoglobin (Hb)

Clinical definition of the hemoglobin test
Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues to the lungs. Hemoglobin molecule contains 2 alpha globulin chains and 2 beta globulin chains. It plays an important role in maintaining the shape of the red blood cells. Abnormal hemoglobin structure distrupts the shape of red blood cells impeding its function and its flow through blood vessels. Hemoglobin test measures the amount of hemoglobin found in red blood cells in a blood sample which is an indicator of the bloods ability to deliver oxygen to the tissues and organs and to transport the waste product carbon dioxide to the lungs, where it is exhaled. Hemoglobin rises when the number of red blood cells increases. When the body decreases its production of red blood cells, hemoglobin falls to less than normal indicating anemia.

Why is the hemoglobin test done?
Hemoglobin test is carried out as a part of CBC count for general health evaluation and to measure and monitor the severity of anemia or polycythemia.

What are the common signs/symptoms when the hemoglobin test is done?

  • Fatigue
  • Weakness
  • Decreased appetite
  • Dizziness
  • Depression
  • Weakness
  • Shortness of Breath
  • General malaise
  • Chest pain
  • Brittle nails
  • Nails, pale skin and gums
  • Cold feet and hands

What should I do before the hemoglobin test?

Specimen type

Specimen collection procedure

Preparatory instructions before the test *


(Blood Sample)


(Collection of blood from a vein, usually from the arm)

No Fasting Required.

No other special preparations required.

*Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my hemoglobin test results?


Normal Hb Value


13.5 – 17.5


12 – 15.6

Children- Age

Day 1 - Day 2

14.0 - 22.0 g/dl

Day 3 - Day 6

15.0 - 21.0 g/dl

Day 7 - Day 13

13.5 - 21.5 g/dl

Day 14 - Day 29

12.5 - 20.5 g/dl

1month  - 1.5 months

11.5 - 16.5 g/dl

2months - 2.5 months

9.4 - 13.0 g/dl

3 months - 6 months

11.1 - 14.1 g/dl

6.5 months - 1 Yr. 11 months

11.1 - 14.1 g/dl

2 Years - 6 Years

11.0 - 14.0 g/dl

6 Years 1 month - 12 Years

11.5 - 15.5 g/dl

Adolescent Male

13 - 16 g/dl

Adolescent Female

12 - 16 g/dl

Hemoglobin, free, urine


Hemoglobin, Plasma

10 – 40 mg/l

*A reference range is a set of values which helps he healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranfes may also vary between labs, in value and units depending on instruments used and method of establishement of reference ranges’’

Diseases/conditions related to the hemoglobin test

Other tests related to the hemoglobin test

  • Complete Blood Count (CBC)

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CBC (Complete Blood Count)