Obstructive Pulmonary Disease (COPD) –
Blood gases test
group of lung conditions, includes; Chronic bronchitis, this is a long-term inflammation of the airways and Emphysema, which is damage to the air
sacs in the lungs. COPD is usually caused by long term smoking which is why it
tends to affect elder people. This is diagnosed using a blood gases test, which
involves taking blood straight from the artery in the wrist and checks for a pH
imbalance and the balance of carbon dioxide and oxygen in the body.
Diabetes – Blood glucose test
Diabetes has two types, type 1 and
type 2 but both affect the body’s blood sugar. Type 1 is due to the body’s immune
system malfunctioning, causing pancreas cells to be harmed, rendering the
pancreas useless and unable to create insulin. Whereas type 2 is due to the
pancreas not being able to produce enough insulin for the body, this is usually
caused by obesity, type 2 is more common than type 1. Diabetes is diagnosed
using a blood glucose test, but there are three types of tests, they are: a
regular glucose test, a fasting glucose test and a glucose tolerance test. A
regular blood glucose test can be done at a hospital or the GP and measures the
body’s glucose levels over the past three months to create an average. A
fasting glucose test involves the patient not eating or drinking for 8 hours or
more before having their levels checked. A glucose tolerance test, involves the
patient fasting before having their levels checked and then taking a glucose
drink and having their glucose levels checked two hours after.
Haemophilia – Coagulation
is a rare inherited blood disorder, it affects the bloods clotting system,
lessening the amount of clotting factors in the blood. This means that people
who have this condition bleed longer than most people. The coagulation test,
specifically the international
normalised ratio, is used to measure the body’s anticoagulants and see if they
are at a normal level. Anticoagulants are the components responsible for
stopping blood clots.
Cystic Fibrosis – Genetic test
Cystic fibrosis affects the lungs, due to there being a
build-up of thick mucus in the lungs, this affects the person’s ability to
breathe and is an inherited condition. A genetic test is done to diagnose
cystic fibrosis, it involves taking some blood and then getting the DNA out of
the sample to search for the genetic mutation.
Arthritis – Erythrocyte
Sedimentation Rate (ESR)
Arthritis is a condition that affects the joints, causing
them to swell and become painful. The test involves taking a sample of the
patients’ blood and measuring how long it takes for the red blood cells to fall
to the bottom of a test tube, if the cells fall quickly then it is likely that
the patient has inflammation.
Mean Corpuscular Volume
Mean Corpuscular Volume is taken
from a full blood count and is the average of the red blood cell volume in the
blood. This test enables doctors to categorise the patients’ level of anaemia,
which could either be macrocytic anaemia, normocytic anaemia or microcytic
anaemia. Macrocytic anaemia occurs when the average is above the normal level,
normocytic anaemia occurs when the average is at a normal level and microcytic
anaemia occurs when the average is below the normal level.
Blood volume tests have two types but overall are used to
work out how much blood is in the body. They work by taking a blood sample,
which then is injected with a dye and is injected back into the patient, once
the mixture has travelled around the body, two more blood samples are taken and
the amount of dyed cells are used to calculate how much blood is in the body. One
of the tests is a plasma volume test and is used the work out a total for the
plasma in the blood, the other test is a red cell volume test, which is used to
work out a total for the amount of red blood cells.
Reticulocytes are red blood cells
before they mature, the bone marrow is responsible for producing them. A
reticulocyte count establishes if the bone marrow is functioning correctly with
regards to producing reticulocytes, this is done by comparing the number of
reticulocytes and red blood cells to obtain a percentage of reticulocytes. This
test can also be used to determine different types of anaemia.
Platelets are produced in the bone
marrow and are fragment cells that circulate the blood, and help form blood
clots. A platelet count gives a number of how many platelets are in the blood
and by observing the count and shape, certain illnesses such as leukaemia and
anaemia can be diagnosed.
Blood smears are tests used to gain
information about the number of blood cells in the blood and their shape.
Tests for abnormal haemoglobin are
completed to observe a patient’s response to treatment for polycythaemia and
anaemia, measure how severe polycythaemia or anaemia are and can be used to
decide if a blood transfusion should be done in the case of severe anaemia.
This is used to observe the levels of
a certain coagulation factor are in the normal range as low levels can cause
bleeding disorders. Most coagulation tests measure the blood’s ability to clot,
more specifically how long it takes to clot.
Red Blood Cell Count
Red blood cell count tests are used
to determine the number of red blood cells in the blood. This can help with
diagnosis of illnesses as red blood cells carry haemoglobin, which carries
oxygen so the less red blood cells the body has the less oxygen is getting to
the tissues and around the body.
Analysis for Iron Deficiency
Iron deficiency is diagnosed using a
blood sample, once it has been taken, it gets sent to a lab where the red blood
cells are analysed along with the level of iron in the blood. Iron deficiency
occurs when the body doesn’t make enough red blood cells, decreasing the amount
of oxygen in the body.
Clinical uses of blood products
The main blood products used in
transfusions are red blood cells, platelets, plasma and cryoprecipitate, these
are used as when a person is in need of blood, they will be given a compatible
blood source but only certain parts of the blood are useful, which is why there
are only four components of the blood used. Blood transfusions have also been
known to give a better quality of life to those who have an incurable illness.
Red blood cells are put in an addictive solution and per
unit, patients can be given a transfusion over 90 to 120 minutes, but once the
cells have been removed from their storage, a transfusion must be given within
four hours. They are usually given to patients with blood loss, anaemia, cancer
or sickle cell.
Plasma cells are frozen and used for blood loss during
childbirth, treatment for anticoagulants, replacing clotting factors and
replacing blood during surgery.
Platelets are used for in
variety of ways, they include: leukaemia treatment, bone marrow failure,
chemotherapy and post-transplant.
Plasma can be processed, giving it
many uses, for example when administered it can help the body create stronger
antibodies to fight illness such as chicken pox or hepatitis. Plasma contains a
protein called albumin that has been known to be advantageous to burn victims.
The main uses for plasma are treating haemophilia but it also can help RhD
negative pregnant women carrying RhD positive babies as it promotes the
production of anti-D.
Effectiveness of Screening Techniques
Each time someone donates blood, they
are asked a to answer a list of questions and a sample is taken and then
screened using various methods. Using the NHS as an example, the infections
that are screened for are syphilis, HIV, Hepatitis C, and hepatitis C. Each
infection has a specific test when being screened, for example, hepatitis C is
tested by searching for an antibody specific to hepatitis C and using a nucleic acid amplification test. HIV is also screened using a test that searches for an antibody
specific to HIV, syphilis is tested for using a test that searches for an anti-treponemal
antibody. Hepatitis B is screened for using a test that searches for the hepatitis
B surface antigen and the hepatitis B core antibody. This is effective as the individual
tests make the process more specific and helps to reduce errors when checking
the blood, and all the screening is done by mahcines which reduces human error,
making the process more effective. The process before donating blood is also
effective as the list of questions gives the medical staff a chance to deny the
donor without having to screen the blood. These methods help to protect people
from acquiring an infection from a blood transfusion.