Also Known As
Hb
Formal Name
Haemoglobin
This article was last reviewed on
This article waslast modified on 19 July 2018.
At a Glance
Why Get Tested?

If you have anaemia (too few red blood cells) or polycythaemia (too many red blood cells), to assess its severity, and to monitor response to treatment

When To Get Tested?

As part of a full blood count (FBC), which may be requested for a variety of reasons

Sample Required?

A blood sample collected from a vein in your arm or by a finger-prick (children and adults) or heel-prick (newborns)

Test Preparation Needed?

Ideally you should be reasonably hydrated when having a haemoglobin test or the result may be inaccurately high.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you will be able to access your results online.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

This test measures the amount of haemoglobin (a protein found in red blood cells) in your blood and is a good indication of your blood's ability to carry oxygen throughout your body. Haemoglobin carries oxygen to cells from the lungs. If your haemoglobin levels are low, you have anaemia, a condition in which your body is not getting enough oxygen, causing fatigue and weakness. If your haemoglobin levels are high, this usually means you have too many red cells which is called polycythaemia. Polycythaemia, when severe, can cause the blood to become too viscous (thick), potentially leading to heart failure, heart attacks or strokes.

How is the sample collected for testing?

A blood sample is collected by inserting a needle into a vein in your arm or by a finger-prick (for children and adults) or heel-prick (for newborns).

Is any test preparation needed to ensure the quality of the sample?

Ideally you should be reasonably hydrated when having a haemoglobin test or the result may be inaccurately high.

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