Hemoglobin test: normal range and what low hemoglobin means

A hemoglobin test measures how much hemoglobin is in your blood. Hemoglobin is the iron-rich protein inside red cells that carries oxygen from the lungs to the rest of the body. It is part of every complete blood count, and it is the number used to define anaemia.

What it measures

Each red cell is packed with hemoglobin. Iron at the centre of the molecule picks up oxygen in the lungs and releases it in the tissues. The test reports how much hemoglobin there is in a given volume of blood, so it reflects both how many red cells you have and how well filled they are. It does not say why a level is low or high; the red cell indices and iron, vitamin B12 and folate results do that.

Normal range

Hemoglobin is reported in g/dL or g/L. The g/L figure is the g/dL figure multiplied by 10, so 13.5 g/dL is 135 g/L.

The World Health Organization sets its adult thresholds, for ages 15 to 65, at the 5th percentile of healthy people, which means about 1 in 20 healthy people sit below them. It grades anaemia in adults as mild from 11.0 g/dL up to the threshold, moderate from 8.0 to 10.9 g/dL, and severe below 8.0 g/dL. Lab ranges vary with the analyser and method, with age and sex, and with altitude, and the range printed on your report is the one to read against.

What low hemoglobin usually points to

Low hemoglobin is anaemia. It is a finding, not a diagnosis, and the cause decides what happens next. Common reasons include:

• iron deficiency, often from heavy periods, pregnancy or other blood loss;
• low vitamin B12 or folate;
• inherited conditions such as thalassaemia;
• long-running inflammation or kidney disease;
• liver disease and, less often, bone marrow conditions.

The red cell indices are the usual next step. Small red cells (a low MCV) point towards iron deficiency or thalassaemia trait, and Ferritin is usually checked next; a ferritin under 15 µg/L in an otherwise healthy person makes iron deficiency likely. Large red cells (a high MCV) point towards low B12 or folate, alcohol or some medicines, and Vitamin B12 is usually checked. A doctor will also ask about periods, diet, digestion and family history.

What high hemoglobin usually points to

A high level often reflects blood concentrated by dehydration rather than extra red cells. When production really is higher, the usual reasons are smoking, lung or heart disease, sleep apnoea, living at high altitude and testosterone use. Polycythaemia vera, a bone marrow condition, is a less common cause. A doctor will usually repeat the test when you are well hydrated and look at hematocrit and the red cell count beside it.

What moves it

• Sex. Men run higher than women.
• Pregnancy lowers it, which is why pregnancy has its own thresholds.
• Smoking raises it. The WHO advises adding 0.3 to 0.6 g/dL to the anaemia threshold for people who smoke, depending on how much.
• Altitude raises it.
• Hydration. Dehydration concentrates the blood and pushes the level up.
• Periods and blood loss lower it.
• Testosterone raises it.
• The sample. The WHO treats venous blood measured on an automated analyser as the reference, and finger-prick results can differ from it.

Preparing for the test

A hemoglobin test needs no special preparation. Clare's panel also includes fasting glucose and fasting insulin, which are measured on a fasting sample, so follow the fasting instructions for the panel as a whole and drink water unless you are told otherwise. Mention pregnancy, smoking, testosterone use, recent heavy bleeding and any known thalassaemia or sickle cell trait to the person taking the sample.

Why it matters in the UAE

Anaemia shows up in UAE studies. In a 2020 study of 251 female university students in Dubai, 18.1% had hemoglobin below 12.0 g/dL on a finger-prick test. In premarital screening in Al Ain, about one in five of 391 healthy young UAE adults tested had iron deficiency.

Inherited red cell traits also shape how hemoglobin is read here. Of 6,420 UAE nationals screened before marriage in Dubai between 2007 and 2010, 4.56% were suspected beta thalassaemia carriers and 2.9% sickle cell carriers. Alpha thalassaemia is common too: in a study of 1,079 UAE citizens, about one in five of those analysed had the small red cells typical of a common variant, and women in that group averaged 12.4 g/dL against 13.4 g/dL in women with normal-sized cells, with likely iron deficiency excluded. Because thalassaemia trait and iron deficiency both give small red cells, a doctor checks ferritin, and sometimes a hemoglobin test for variants, before putting a low result down to iron.

For people who fast in Ramadan, a 2025 review by haematologists in Saudi Arabia notes that daytime fluid restriction can concentrate the blood, that some studies found a modest fall in hemoglobin by the end of the month, and that fasting does not in itself cause anaemia when iron and calorie intake are enough. It treats severe anaemia, below 8 g/dL, as a reason not to fast. If your result is low and you plan to fast, talk to a doctor before Ramadan, with the result in front of you.

How Clare's panel handles it

In Clare's panel, hemoglobin is measured by the lab as part of the complete blood count. HbA1c, also in the panel, is a different number: the share of hemoglobin with sugar attached, which tracks average blood sugar.

Price in the UAE

Hemoglobin is usually sold within the CBC blood test rather than on its own. When we read public prices on 11 October 2026, a CBC cost from 35 to 149 at 7 UAE providers. VAT is rarely stated, some are "from" or package prices, and home collection can add a fee.

Related tests

Ferritin shows iron stores, the Mean Corpuscular Volume (MCV) the size of the red cells, and Vitamin B12 and Folate the vitamins red cells need. Hematocrit and the Red Blood Cell Count (RBC) describe oxygen-carrying capacity from other angles, and the CBC blood test brings them together. Comprehensive blood test in Dubai: what to expect explains why drinking water before a draw matters for this result.

Why the number means more over time

One slightly low value in someone who feels well is often simply repeated. A steady fall across several results, even inside the range, says more, and is worth a conversation with a doctor with the results in front of you. When someone is treated for anaemia, the doctor rechecks hemoglobin to see whether it is coming back up. A blood count is commonly part of a routine check-up, so a personal baseline builds without extra tests.

Clare is opening with a waitlist at clare.health.