deathchibi wrote:
Red blood cells
One of the most important red blood cell tests is used to find out how much haemoglobin there is in the blood. Haemoglobin carries oxygen around your body. This is called the haemoglobin concentration or level.
Another important test, the mean corpuscular volume or MCV test, measures the size of the red blood cells.
If a person suffers from anaemia their haemoglobin level will always be less than normal. But the size of the red blood cells depends on the type of anaemia you have.
A haematocrit test measures the total volume that red blood cells take up in the blood. In practice, this is done by spinning a test tube of blood until the red blood cells - the heaviest part of the blood - go to the bottom of the tube. Then their volume is calculated.
Almost all types of anaemia will cause a low haematocrit (a low red blood cell volume), as will very severe bleeding. A high haematocrit can occur if a person is dehydrated from not drinking enough fluid or because they are losing fluid as happens with diarrhoea, burns and sometimes surgery.
If the red blood cells are pale, it can be a sign of iron deficiency anaemia. If they have a strange shape, it may be because of sickle cell anaemia or pernicious anaemia.
Doctors also add stains to the blood smear to test the blood for parasites, for example in the case of sleeping sickness or malaria. They may also test for bacteria in the case of blood poisoning.
White blood cells (WBC)
The doctor counts the total number of white blood cells and works out how many different types of white blood cells the patient has. This is called the differential WBC count.
The number of white blood cells may go up and this may be because of a bacterial infection, bleeding or a burn. More rarely the cause of a raised white count is due to leukaemia, cancer or malaria.
A person may lose white blood cells because they have autoimmune problems - this is where the antibodies that should fight diseases attack the body instead. Other reasons for loss of white blood cells include viral infections. More rarely, this can be a side effect of certain kinds of medication.
Doctors keep an eye on white blood cells to work out how a disease is changing. By monitoring the blood count in this way they can alter the patient's treatment as necessary.
Platelets
Platelets are very small cells in the blood that clump together at sites of injury to blood vessels. They form the basis of the blood clot that would form if you cut yourself.
Low numbers of platelets can make a person vulnerable to bleeding, sometimes even without injury occurring. Causes of low platelet counts include autoimmune diseases where you produce an antibody to your own platelets, chemotherapy, leukaemia, viral infections and some medicines.
High numbers of platelets make a person more vulnerable to blood clots. High platelet counts are found in conditions involving the bone marrow such as leukaemia and cancer.
if your saying what I think you're saying;
that's digusting!
10 Apr 2008, 8:05 am
