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Hemoglobin: what the test means in plain English

Hemoglobin is the part of your red blood cells that carries oxygen around your body. A hemoglobin test measures how much of it is in your blood.

Usually reported in g/dL (grams per deciliter).

For education only. Lucidio does not diagnose, treat, or replace a doctor. Lab results should always be interpreted by a healthcare professional using the patient's symptoms, history, exam, and full lab report.

What this test measures

Hemoglobin is a protein inside red blood cells. It picks up oxygen in your lungs and drops it off everywhere else.

The test reports one number, usually in grams per deciliter (g/dL), next to a reference range printed by the lab that ran it.

Reference ranges are not the same everywhere. They differ by lab, and by things like age and sex, so always read your number next to the range on your own report.

What low, normal, and high generally refer to

These are general descriptions of the words on a lab report — not an interpretation of your result.

Below the range

A result under the range means less hemoglobin than the lab expects for that group of people. Many different things can cause this, and only a clinician who knows your history can say what it means for you.

Within the range

A result inside the range is what the lab considers typical. It is one measurement on one day, not a verdict on your overall health.

Above the range

A result over the range means more hemoglobin than expected. Like a low result, the reasons vary widely and need a clinician to sort out.

Why a doctor might order it

  • As part of a routine complete blood count (CBC) during a general check-up.
  • When someone reports feeling unusually tired, short of breath, or lightheaded.
  • To keep an eye on a condition or treatment already being managed.
  • Before or after a procedure, when a clinician wants a baseline.

Questions worth asking

  1. 1What is my hemoglobin number, and what range did this lab use?
  2. 2Is this a change from my last result, or has it been steady?
  3. 3Does this number explain how I have been feeling, or is it unrelated?
  4. 4Do you want to repeat the test, and if so, when?

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Source: MedlinePlus: Hemoglobin Test