Formal Name
Preoperative Tests
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This article waslast modified on 26 June 2023.

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, 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 red cells, white cells and platelets in your blood.. It is used to identify conditions such as anaemia or thrombocytopenia (low platelet count) 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. 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 idea of how well the kidneys are working, and detect urinary tract infections.
Kidney function tests
A collection 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 condition, e.g.asthma or bronchitis.
Chest X-ray
A chest X-ray may be taken before your operation if you are undergoing chest or abdominal surgery, have a history of lung or heart disease, history of recent chest trauma or are a heavy smoker.
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 65), have a history of cardiac symptoms (breathlessness, fainting, chest pain, heart failure), are diabetic or have renal problems.
This is a sleep study and usually involves staying overnight at a sleep centre where your sleep pattern is measured. Sensors are placed on your body whilst you sleep which monitor:
  • Brain waves.
  • Heart rate and blood oxygen levels.
  • Eye movements.
  • Air flow through your mouth and nose.
  • Muscle tone and movement.
The results of the study are then interpreted by a specialist.
MRSA screening
Methicillin resistant Staphylococcus aureus (MRSA) is a bacteria. It usually lives harmlessly on the skin but can cause infection once it enters the body, particularly in people with poor health.You are likely to be screened for MRSA if you require admission to hospital for planned or emergency care, especially if you have previously had MRSA colonisation or infection and are being admitted to a high risk unit ( e.g. surgery, trauma, dialysis, intensive care and cancer). Usually screening is done before admission to hospital, in a pre-admission clinic or GP surgery. The test is done by taking swabs (like a cotton bud) from various areas of the body (e.g. inside of the nostrils, groin and the back of your mouth). If MRSA is found, you are MRSA positive and need to treat it using a special nasal cream /spray, body wash and shampoo. Sometimes antibiotics may be needed, mild MRSA infection can be treated using tablets. Serious infections may need treatment using antibiotics given by injection or drip in hospital. Antibiotics may be given for a few days to months depending on the severity of the infection.