Your blood count
Exceptional healthcare, personally delivered
Your blood count
The circulation
Blood moves around the body inside the blood
vessels called arteries, veins and capillaries. Blood
is pumped through these vessels by the heart.
What is blood made of?
The average adult human has about 5 litres
(just under 9 pints) of blood. About 50% of the
blood is made up of plasma constituting the
fluid part of the blood. The cells and platelets
that are present in our blood make up the other
50%.
Red cells
Red blood cells
Red blood cells make up about 45% of the
blood volume and give it colour.
Neutrophil
There are more than 4 million of them in every
cubic millimeter of blood. A red blood cell
can live for up to 120 days and new ones are
constantly being made.
Red blood cells carry oxygen to the tissues.
When they get to an area where the oxygen
is needed, they give it up and pick up carbon
dioxide that they carry back to the lungs.
Anaemia is a lack of red blood cells.
Lymphocyte
White blood cells
There are several different types of white blood
cells that together make up about 3% of blood.
The most numerous are the neutrophils. They act
in the body’s response to bacterial infection, can
be made very quickly and have a short lifespan.
2
Your blood count
Eosinophil
The next most numerous are lymphocytes, part
of the immune system and involved in making
antibodies.
Monocytes, eosinophils and basophils are other
white cells that are present in smaller numbers.
Platelets
Platelets make up about 2% of the blood.
They are small bits of much bigger cells
(megakaryocytes, found in the bone marrow).
When blood clots they clump together to form
a plug and then secrete factors that help make
the clot and start repair of the damaged blood
vessel.
Monocyte
Where are blood cells made?
All blood cells develop from a ‘blood stem cell’
found in the bone marrow of the skull, ribs,
sternum (breast bone), spine and pelvis. For
this reason, a sample (biopsy) of bone marrow
can be examined under the microscope and
tested in other ways to help to find the cause
of an abnormality in the blood count.
Basophil
Plasma
Plasma is 92% water, 7% protein, 1%
minerals, plus vitamins, sugar, and fats. It also
contains clotting factors and antibodies. Plasma
carries nutrition to all parts of the body and
then carries away waste products for removal
from the body.
Platelets
Your blood count
3
What is a full blood count?
A blood sample is taken, usually from a vein. It is prevented from
clotting by a chemical in the blood bottle so that it will remain
liquid for analysis. The blood tube is put into a machine which
sucks out a sample and automatically:
nn Measures the haemoglobin.
nn Counts the number of red cells, white cells, and platelets.
nn Measures the size of the red blood cells.
nn Calculates the proportion of blood made up from red blood
cells (the haematocrit).
These results are known as a full blood count.
Full Blood Count Reference ranges:
Man
Woman
Haemoglobin g/dl
13.0 - 17.0
11.5 - 16.0
Haematocrit
0.4 - 0.54
0.37 - 0.47
White cells x109/l
4.0 - 11.0
4.0 - 11.0
Neutrophils x109/l
2.0 - 7.5
2.0 - 7.5
Lymphocytes x109/l
1.5 - 4.0
1.5 - 4.0
Monocytes x109/l
0.2 - 0.8
0.2 - 0.8
Eosinophils x109/l
0.04 - 0.4
0.04 - 0.4
Basophils x109/l
0 - 0.1
0 - 0.1
Platelets x109/l
150 - 400
150 - 400
NHS Constitution. Information on your rights and responsibilities.
Available at www.nhs.uk/aboutnhs/constitution
4
Your blood count
How to contact us:
See your appointment letter for the
number to phone with any queries
you may have
www.nbt.nhs.uk
If you or the individual you are caring for need support reading
this leaflet please ask a member of staff for advice.
© North Bristol NHS Trust. This edition published May 2014. Review due May 2016. NBT002080