In brief
Blood transports oxygen, nutrients, minerals and hormones around the body. Red blood cells carry oxygen using haemoglobin, an iron-containing protein.
- A full blood count counts and measures red blood cells, white blood cells and platelets.
- Small red cells are linked with iron deficiency, while large red cells are linked with low vitamin B12 or folate.
- A flagged blood test result does not necessarily mean that anything is wrong.
How it works
Blood contains red blood cells, white blood cells, which are the key players in the immune system, and platelets, which help blood clot. Most bones contain bone marrow, where blood cells are made.
Making red blood cells needs iron, vitamin B12 and folate, and hormones from the kidneys help control red blood cell production. Anaemia means you do not have enough red blood cells or haemoglobin. It is commonly caused by iron deficiency and can make you tired and weak.
Connections
10 connections on the map. Select a topic to read its page.
Blood and red blood cells needs
Your body uses iron to make haemoglobin, the protein in red blood cells that carries oxygen.
Sources: NIH Office of Dietary Supplements, Iron fact sheet for consumers; Pathology Tests Explained, Full blood count
Vitamin B12 and folate are needed to make red blood cells.
Your body uses folate to form red blood cells.
Source: healthdirect Australia, Folate
Your body needs vitamin K to make proteins for blood clotting.
Sources: NIH Office of Dietary Supplements, Vitamin K: fact sheet for health professionals; NIH Office of Dietary Supplements, Vitamin K fact sheet for consumers
Blood and red blood cells is supported by
The lungs take up oxygen from the air, and red blood cells carry it using haemoglobin.
Sources: Better Health Channel (Victorian Government), Respiratory system; Pathology Tests Explained, Full blood count
Hormones from the kidneys help control red blood cell production.
Source: Better Health Channel (Victorian Government), Kidneys
Folate is needed to make DNA and to form red blood cells.
Sources: NIH Office of Dietary Supplements, Folate: fact sheet for health professionals; healthdirect Australia, Folate
Blood and red blood cells is part of
Blood transports nutrients, minerals and hormones throughout your body.
Blood and red blood cells is affected by
Anaemia is when you do not have enough red blood cells or haemoglobin.
Source: healthdirect Australia, Anaemia
Blood and red blood cells is measured by
A full blood count counts and measures red blood cells, white blood cells and platelets.
Lab tests
- Full blood count (FBC)One of the most common blood tests. It counts and measures red blood cells, white blood cells and platelets.
- Iron studies (including ferritin)A group of blood tests that shows how much iron is stored in your body and how much is being carried in the blood.
- Vitamin B12 and folate testsBlood tests for vitamin B12 and folate, usually ordered after a full blood count shows a problem, or for nerve symptoms.
Medicines and supplements
General education only. Never start, stop or change a medicine without your prescriber.
Sources
Each connection above names its own source. See every source AskBioMap uses.
Summarised from Pathology Tests Explained, the Better Health Channel and healthdirect. Sources read on 13, 16 and 19 October 2026. General education only, not medical advice. Spotted a mistake? Please tell us through the HuBu-Intel contact page.