What your blood test results mean
Your blood test will check the levels of different substances in the blood. Do not worry if the results seem confusing at first. Your doctor will look at certain levels to see if you have iron deficiency (ID) or iron deficiency anaemia (IDA).
Haemoglobin
Haemoglobin levels show how much oxygen the blood can carry around the body. This will tell your doctor whether you have anaemia, and how severe it is.
Haemoglobin levels to diagnose anaemia (g/dl)1
| No anaemia | Mild anaemia | Moderate anaemia | Severe anaemia | ||
| Children aged 6-59 months | 11.0 and above | 10.0-10.9 | 7.0-9.9 | Less than 7.0 | |
| Children aged 5-11 years | 11.5 and above | 11.0-11.4 | 8.0-10.9 | Less than 8.0 | |
| Children aged 12–14 years | 12.0 and above | 11.0-11.9 | 8.0-10.9 | Less than 8.0 | |
| Non-pregnant females aged 15 years and above | 12.0 and above | 11.0-11.9 | 8.0-10.9 | Less than 8.0 | |
| Pregnant females | 11.0 and above | 10.0-10.9 | 7.0-9.9 | Less than 7.0 | |
| Males aged 15 years and above | 13.0 and above | 11.0-12.9 | 8.0-10.9 | Less than 8.0 | |
Adapted from World Health Organization. 2011.
To see if you have ID/IDA, your doctor will also need to look at how much iron you have.
Ferritin
Ferritin is a protein that is used to store iron. Some ferritin can be found in the blood, so measuring it can show how much iron you have. If the level is low, it may mean that you have ID.
Ferritin levels to diagnose ID (μg/l)2
| Apparently healthy people | People with infection or chronic inflammation | ||||
| No iron deficiency | Iron deficiency | No iron deficiency | Iron deficiency | ||
| Children aged 0-4 years | 12 and above | Less than 12 | 30 and above | Less than 30 | |
| Children and adolescents aged 5-19 years | 15 and above | Less than 15 | 70 and above | Less than 70 | |
| Adults aged 20 years and above | 15 and above | Less than 15 | 70 and above | Less than 70 | |
Adapted from World Health Organization. 2020.
Your haemoglobin and ferritin levels will help your doctor to reach a diagnosis, but they may also need to look at other blood test results.3 These may include:3,4
- Haematocrit (the amount of red blood cells in the blood)
- Mean cell volume (the average size of red blood cells)
- Mean cell haemoglobin (the average amount of haemoglobin in red blood cells)
- Serum iron level (the amount of iron in the blood)
- Transferrin saturation (the percentage of iron transporters in the blood that are carrying iron)
- Total iron binding capacity (the amount of iron the blood can take up)
LEARN ABOUT IRON MEDICINES
REFERENCES
- World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. 2011.
- World Health Organization. WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. 2020.
- NICE. What investigations should I arrange to confirm iron deficiency anaemia? Available at: https://cks.nice.org.uk/topics/anaemia-iron-deficiency/diagnosis/investigations/#interpreting-a-full-blood-count. Accessed December 2021.
- American Society of Hematology. Iron deficiency anemia. Available at: https://www.hematology.org/education/patients/anemia/iron-deficiency. Accessed December 2021.
