Preoperative tests are a set of tests that are carried out before you have a planned (sometimes called 'elective') operation. These tests may be done even if you appear to be healthy, to provide information about conditions that could affect the treatment you need.
The tests that you have done before your operation will be determined by your age, your general health, any illnesses you have or any medication you are on, and the type of operation you are going to have.
The range of preoperative tests recommended by the National Institute for Health and Care Excellence (NICE) includes:
- Full blood count (FBC)
- This is a measure of haemoglobin and the number of other types of cells in the blood. This can identify conditions such as anaemia or thrombocytopenia which may mean extra precautions need to be taken to reduce your risk of bleeding during surgery.
- Blood clotting tests
- These tests are carried out to check if your blood clots normally and how long it takes to clot. They may be done if you are on blood-thinning drugs such as warfarin, are on kidney dialysis, or if you have liver or blood vessel (vascular) disease.
- Blood gases
- This test measures the amount of oxygen and carbon dioxide in the blood. This may be carried out before your operation if you have lung or heart disease.
- Blood glucose
- This test can be used to tell if you have diabetes before undergoing any major surgery. Diabetes can have an effect on recovery from surgery, so it is important to know this in advance so that any necessary precautions can be taken.
- Urine dipstick test
- This test is used to detect certain substances in the urine that may indicate disease, for example glucose in the urine may indicate diabetes. It can also give an indication of how well the kidneys are working, and detect urinary tract infections.
- Kidney function tests
- These involve a variety of tests on both blood and urine samples to determine how well your kidneys are working, and will usually be checked before any major operation.
- Sickle cell test
- Sickle cell anaemia is an inherited disease that affects the ability of haemoglobin in your red blood cells to carry oxygen. If you inherit the sickle cell gene from both parents then you will have sickle cell anaemia, which causes serious health problems. If you inherit the gene from only one parent then you will have 'sickle cell trait', which causes no symptoms but means you are a 'carrier' of the sickle cell gene. If you have sickle cell anaemia or sickle cell trait then having a general anaesthetic may cause problems, therefore if you are of an ethnic origin considered to be at risk of sickle cell disease you should have this test before you have an operation.
- Pregnancy test
- If there is any chance you may be pregnant then this test should be performed before an operation, as anaesthesia and surgery may harm your unborn baby.
- Lung function tests
- These are used to check how efficiently you breathe and may be carried out before surgery if you have any type of lung disease, e.g.asthma or bronchitis.
- Chest X-ray
- A chest X-ray may be taken before your operation if you are an older person (over 60) with lung or heart disease and you are undergoing major surgery.
- Electrocardiogram (ECG)
- This test is used to detect problems with the heart such as an abnormal heart rhythm. It may be carried out before your operation if you are an older person (over 60) with chest pain or a history of heart disease and you are undergoing major surgery
- MRSA screening
- Methicillin resistant Staphylococcus aureus (MRSA) is a bacteria (glossary). The bacteria live in many people’s skin without causing any harm, but it causes infection once it enters the body, particularly in people with poor health. This test is done to detect the presence of this bacteria on your body. You are likely to be screened for MRSA if require admission to hospital for planned or emergency care, if you have previously had MRSA colonisation or infection and require admission to a high risk unit ( e.g. surgery, trauma, dialysis, intensive care and cancer). You are generally not screened if you are not staying overnight. Usually screening is done before admission to hospital, in a pre-admission clinic, GP surgery or outpatient clinic. The test is done by taking swabs (like a cotton bud) from various areas of the body (e.g. nose, groin, armpit, wound, catheter sites or damaged skin). If the MRSA bacteria is found in any part of the body, you would be MRSA positive. In order to get rid of the MRSA bacteria from your body, a body wash may be prescribed. Sometime additional throat gargle, wound ointments or antibiotics might be required. At least 3 cycle of treatment is given and you would be screened again after the treatment. Once you are clear from the MRSA bacteria you are classed as MRSA negative. In order to minimise further risk of the infection, intravenous antibiotics may be administered around the time of surgery.