YOU may wince as the needle goes in, but once your blood has been taken do you give second thought to what happens to it after your blood test?

National Pathology Week aims to raise awareness of what happens to our samples once they have left our bodies and how they can help in the diagnosis of disease.

Over 70 per cent of conditions diagnosed in the NHS involve pathology.

The pathology department at Basildon Hospital is open 24/7, employing about 17 doctors, 200 scientific staff and 60 support staff, who process more than 2,000 samples a day.

About 40 per cent of samples sent for testing come from GPs, while the remainder are received from hospital inpatients and outpatients, along with urgent samples arriving from the A&E department.

One of the most common tests undertaken is for cholesterol, which is used to estimate the risk of developing heart disease, and is a routine part of preventative health care. High blood cholesterol is associated with the hardening of the arteries, heart disease and an increase risk of death from heart attacks.

Once diagnosed, pathology investigations are involved in the monitoring and treatment of heart disease in order to provide patients with a better quality of life.

The UK has one of the highest rates of cardiovascular heart disease in the world, and it is the most common cause of death, with 90,000 people dying from the disease every year.

Cardiovascular disease is caused by a gradual build up of fatty deposits on the walls of the coronary arteries. This causes the artery to narrow, and makes it harder for the artery to supply the heart muscle with blood and oxygen. The fatty material is known as atheroma.

Dr Gautam Chajed, a GP from Kingswood Medical Centre, Basildon, says: “Heart attacks tend to occur when a piece of the fatty atheroma breaks away from the artery wall and causes a blood clot to form; this clot then blocks the artery, starving the heart muscles of blood and oxygen. However, early detection and changes to lifestyle can greatly reduce and even prevent the onset of coronary disease.”

But how does your GP know when you have a heart-related problem, which could lead to heart disease? They rely on the invaluable work of the pathology department, which provides investigations on blood, urine and other material.

Cholesterol may be measured with other blood fats as part of a lipid profile in order to provide a better estimate of the risk of heart disease; this includes measurement of total cholesterol, LDL-cholesterol or ‘bad cholesterol’, HDL-cholesterol or ‘good cholesterol’ and the triglycerides.

The patient will also be screened against other risk factors known to contribute to heart disease, such as smoking, high blood pressure, diabetes, or a family history of heart disease. Tony Everitt, consultant biochemist at Basildon Hospital, says: “In the modern NHS, preventative medicine is important and pathology plays a vital part in ensuring patients at risk from heart disease are detected and offered appropriate advice and treatment.”

To measure cholesterol, a simple blood test is carried out. The patient must not eat for 12 hours before the test – this ensures all food is completely digested and will not affect the outcome of the test.

Most blood samples are taken by trained phelebotomists and, once taken, the blood sample must reach the hospital’s pathology laboratory within four hours.

Samples are transported to the laboratory by a variety of means and urgent samples from A&E arrive via a vacuum tube. Once in pathology, the patient’s details on the sample are checked against the GP’s request form, before a new unique barcode is added to the sample and form.

The form is scanned and indexed against the laboratory system and patient’s details are typed into the pathology database.

The sample is then put into a centrifuge, which is a machine that spins the blood to separate the red cells from the serum.

The blood sample is then transferred to one of two analysers, affectionately known as “Bert” and “Ernie”, and loaded into a metal rack; the barcode label is scanned to determine which tests have been requested by the GP before testing begins. A single sample can be used for up to 30 different tests, which take about 20 minutes to complete.

Mr Everitt explains: “Bert and Ernie can process approximately 5,000 tests per hour. The results are then sent electronically to a validation station where they are checked, before the results are reported.

“Ten years ago, all results were printed onto paper reports and sent back to GPs using a courier system. Today, 95 per cent of test results are transferred electronically into the patient’s record on the GP surgery system. It is just as well, since two million test results a year are sent from the hospital to GPs across the area.”

Once the results are back, the GP examines the results of the cholesterol test against the patient’s known risk factors, in order to assess the patient’s risk of developing heart disease, and if so what type of treatment is required.

A patient with a raised cholesterol level may require treatment, initially in the form of changes to their lifestyle, such as giving up smoking or adopting a diet that’s low in saturated fats.

If diet cannot lower cholesterol enough, drugs such as statins are used.

Statins reduce the amount of cholesterol made in each cell, and forces the body to gather excess cholesterol from the blood stream, thereby reducing the overall blood cholesterol levels.

Mr Everitt adds: “The use of high-technology analysers, along with IT developments, have enabled us to establish an efficient pathology service for the entire district, and by working closely with local GPs we are able to deliver a high quality of care to all our patients.”