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Blood tests can be used in a number of ways, such as helping to diagnose a condition, assessing the health of certain organs or screening for some genetic conditions.
This page describes the following commonly used blood tests:
For more information about a wider range of tests, search theÂ blood test A-Z index on Lab Tests Online UK.
Cholesterol is a fatty substance mostly created by the liver from the fatty foods in your diet and is vital for the normal functioning of the body.
Blood cholesterol levels can be measured with a simple blood test. You may be asked not to eat for 12 hours before the test (which usually includes when you're asleep) to ensure that all food is completely digested and won't affect the result, although this isn't always necessary.
ThisÂ involves taking a small sample of blood from a vein in your arm and from one or more other parts of your body.
The samples are combined withÂ nutrients designed to encourage the growth of bacteria. This can help show whether any bacteria are present in your blood.
Two or more samples are usually needed.
Read more aboutÂ blood cultures on Lab Tests Online UK.
A blood gases sample is taken from an artery, usually at the wrist. It's likely to be painful and is only carried out in hospital.
A blood gas test is used to check the balance of oxygen and carbon dioxide in your blood, and the balance of acid and alkali in your blood (the pH balance).
A pH imbalance can be caused by:
Read more aboutÂ blood gas tests on Lab Tests Online UK.
A number of tests can be used to diagnose and monitorÂ diabetes by checking the level of sugar (glucose) in the blood.
These include the:
Blood glucose test kitsÂ may be available to use at home. These only require a small "pin prick" of blood for testing.
Read more aboutÂ glucose tests on Lab Tests Online UK.
If you were given blood that didn't match your blood group, your immune system may attack the red blood cells, which could lead to potentially life-threatening complications.
Blood typing is also used during pregnancy, as there's a small risk the unborn child may have a different blood group from their mother, which couldÂ lead to the mother's immune system attacking herÂ baby's red blood cells. This isÂ known as rhesus disease.
If you don’t already know your blood type, your blood will be tested at least once during your pregnancy to determine if there’s a risk of rhesus disease. Read more about diagnosing rhesus disease.
If testing reveals there is a risk of rhesus disease, an injection of a medicine that stops the mother's immune system attacking her baby's blood cells can be given. Read more about preventing rhesus disease.
Read more aboutÂ blood typing on Lab Tests Online UK.
A number of blood tests can be carried out to help diagnose certain cancers or check if you're at an increased risk of developing a particular type of cancer.
These include tests for:
This is a test toÂ examine bundles of genetic material called chromosomes.
By counting the chromosomes (each cell should have 23 pairs) and checking their shape, it may be possible to detect genetic abnormalities.
Chromosome testingÂ can be used:
A coagulation test may be used to see if your blood clots in the normal way.
A type of coagulation test called the international normalised ratio (INR) is used to monitorÂ the dose of anticoagulants, such as warfarin, and check that your dose is correct. Read more about monitoring your anticoagulant dose.
This isÂ another test used to helpÂ diagnose conditions that cause inflammation.
CRP is produced by the liver and if there is a higher concentration of CRP than usual,Â it's a sign ofÂ inflammation in your body.
Read more aboutÂ C-reactive protein on Lab Tests Online UK.
Electrolytes are minerals found in the body, including sodium, potassium and chloride, that perform jobs such asÂ maintaining a healthy water balance in your body.
Read more aboutÂ electrolytes on Lab Tests Online UK.
This test works by measuring how long it takes for red blood cells to fall to the bottom of a test tube. The quicker they fall, the more likely it is there are high levels of inflammation.
An ESR is often used to help diagnose conditions associated with inflammation, such as:
Along with other tests, an ESR can also be useful in confirming whether you have an infection.
Read more aboutÂ erythrocyte sedimentation rate on Lab Tests Online UK.
ThisÂ is a test to check the types and numbers of cells inÂ your blood, including red blood cells, white blood cells and platelets.
This can help give an indication of your general health, as well as provide important clues about certainÂ health problems you may have.
For example, an FBC may detect signs of:
Read more aboutÂ full blood count on Lab Tests Online UK.
ThisÂ involves extracting a sample of DNA from your blood, then searching the sample forÂ a specificÂ genetic change (mutation).
Genetic conditions that can be diagnosed this way include:
Genetic screening can also be used to check if someone carries a particular gene that increases their risk of developing a genetic condition.
For example, if your brother or sister developed a genetic condition in later life, such as Huntington's disease, you may want to find out whether there is a risk that you could also develop the condition.
Read more about genetic testing.
When the liver is damaged, it releases substances called enzymes into the blood and levels of proteins produced by the liver begin to drop.
By measuring the levels of these enzymes and proteins, it's possible to build up a picture of how well the liver is functioning.
Read more aboutÂ liver function tests on Lab Tests Online UK.
This test is used to test your blood for levels of thyroid-stimulating hormone (TSH), and, where needed, thyroxine and triiodothyronine (thyroid hormones).
Read more aboutÂ thyroid function tests on Lab Tests Online UK.
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