Home › Biomarkers › Hemoglobin
In a prospective study among community dwelling men and women aged 65 and over, 8.5% had anaemia by the criteria of the World Health Organization.[1]
On this page you can read what haemoglobin is, what the guidelines say about a value that is too low or too high, what influences your value and which values you are best off reading alongside it.
Also known as: Hb, Hgb, H&H. At the lab: KBB.
Hemoglobin is an iron-rich protein in your red blood cells. It carries oxygen from your lungs to the rest of your body. Your cells need that oxygen to grow, to multiply and to make energy. Other names for this value are Hb, Hgb and H&H.[2]
A hemoglobin test measures how much hemoglobin there is in your blood. Your value gives information about the health of your red blood cells. If the value is abnormal, that can point to a blood condition. The value is usually measured as part of the blood count, a group of tests that measures the number and the type of cells in your blood.[2]
A hemoglobin test is not the same as a hemoglobin A1C test. That A1C test is used to look at your average blood glucose, in other words your blood sugar. For the hemoglobin test itself you do not need to prepare in any special way. If the doctor has ordered other blood tests as well, you may need to go without food for a few hours.[2]
With anaemia, the cells in your body do not get all the oxygen they need. Symptoms that go with anaemia are weakness, dizziness and cold hands and feet. That is why a doctor looks at your hemoglobin when you have symptoms like these.[2]
A doctor may order the test at a routine check-up. Other reasons are an inherited blood condition in the family, a diet low in iron and other minerals, or heavy blood loss from a wound or an operation. The test is also used to follow how a value develops during care for anaemia.[2]
The Cardiovascular Health Study followed 5,888 community dwelling men and women aged 65 and over, with 11.2 years of follow-up. Both lower and higher haemoglobin values and anaemia by the criteria of the World Health Organization were independently linked there to a higher mortality. Correcting for kidney function, inflammation or frailty did not make that link smaller.[1]
The test cannot say what an abnormal value comes from. It does help the doctor work out how serious the situation may be. To read your result, the doctor also looks at your symptoms, your history and the results of other blood tests.[2]
The laboratory BioProfile works with, Labplusarts, uses a reference value for haemoglobin (KBB) of 8.3 to 10.7 mmol/l. A value between those limits is what the lab calls normal.[3]
| Value | What it can mean | Who it is for |
|---|---|---|
| Lower than 13 g/dl[1] | Anaemia according to the criteria of the World Health Organization; in the study, linked to a higher death rate | Men aged 65 and over in the study |
| Lower than 12 g/dl[1] | Anaemia according to the criteria of the World Health Organization; in the study, linked to a higher death rate | Women aged 65 and over in the study |
| Lower than 13.7 g/dl[1] | Lowest fifth of the values; in the study this went together with a higher mortality than the fourth group | Men aged 65 and over in the study |
| Lower than 12.6 g/dl[1] | Lowest fifth of the values; in the study this went together with a higher mortality than the fourth group | Women aged 65 and over in the study |
| Highest fifth of the values[1] | In the study this went together with a higher mortality than the fourth group | Men and women aged 65 and over in the study |
Cut-off values from the Cardiovascular Health Study, a prospective study of 5,888 community-dwelling men and women aged 65 and over in the United States, with 11.2 years of follow-up. The cut-offs hold for that group, not as a general standard.[1]
A low hemoglobin value can point to various forms of anaemia, to an inherited blood condition, to iron deficiency, to a condition of the liver or to other conditions. Blood loss from a wound, from a heavy period or from something else can lower your value too. A shortage of certain nutrients, such as iron or vitamin B-12, can play a part as well.[2]
A high hemoglobin value can point to a disease of the lungs, to a heart condition, to a bone marrow condition in which the marrow makes too many red blood cells, or to a condition in which you keep stopping breathing during sleep. Living at high altitude can give a high value too. So a value outside the range does not always mean there is a condition.[2]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
What you eat can influence your result. A diet low in iron and other minerals is a reason for a doctor to have your haemoglobin measured. A shortage of iron or of vitamin B-12 can go together with a low value.[2]
Certain medicines can affect your result. Dehydration can change your value too. So tell the doctor which medicines you take.[2]
Living at high altitude can give a high haemoglobin value, even when nothing is wrong. Smoking can influence your result. How much you move plays a part as well.[2]
The reference range can differ from one laboratory to another and with age, background and sex. Certain genetic conditions can affect your result too. So compare your value with the range of the lab that looked at your blood.[2]
Hemoglobin is in all five packages, from BioProfile 31 to BioProfile 150.[4]
The BioProfile editorial team wrote this page on 30 September 2026 from the sources below, which we read on 30 September 2026. Every number on this page appears in one of those sources, with the number of that source next to it. An expert still has to review this page; after that review, the name of that expert and the date of the review appear at the top. This page gives an explanation, not a diagnosis. Discuss an abnormal value with your GP.
