Blood Safety

Quality is regarded as of paramount importance at the Northern Ireland Blood Transfusion Service. This commitment is demonstrated by the development of a quality management system which will ensure the provision of safe, efficacious and timely blood products and services for both patients and donors The Northern Ireland Blood Transfusion Service (NIBTS) Quality Statement indicates our committment to safety. Safety is included as an integral part of quality and NIBTS aims to provide blood and blood components that are as "safe" as possible

Quality Systems

The Blood Safety and Quality Regulations (2005) set out specific requirements for the collection, processing, testing and distribution of blood and blood components. This is supported by further detailed guidance relevant to pharmaceutical industries and specifically in the Guidelines for Blood Transfusion Services in the UK. The NIBTS quality system is based on these statutory requirements and guidance and also reflects current International Standards for Quality Systems. These standards are recognised throughout the world as important foundations on which to build quality, and hence safety in blood and blood components.

Within the procedures of this quality system are key steps targeted specifically at assuring the safety of blood and blood components, and also blood donors.

A Shared Responsibility - Donor Screening

Blood Safety does begin with the donor. In order to keep blood safe donors are asked a series of questions covering health, travel and lifestyle. It is essential that donors recognise that these questions are as important as the sensitive tests applied within NIBTS laboratories in making sure blood is safe.

Donor Screening is performed by appropriately trained and qualified staff. The key objective is to protect the health of the donor and the patient who receives the blood. The detailed questioning and documentation aims to ensure that blood is not taken from any donor who will suffer ill effect as a result of the donation or from any donor who has the potential to transmit any form of infectious disease e.g. HIV. It should be noted that donors are not at risk of contracting infectious diseases during the donation process.

Haemoglobin Screening is performed on all donors using a number of methods. In addition to tests performed at sessions, NIBTS staff take samples which allow such tests to be performed within the laboratories using more sensitive techniques, and hence provide improved donor care.

Collection and Production

Following the screening process donors will progress to donate approx. 470 ml of their blood. The venepuncture site is cleaned with antiseptic to reduce the potential of introducing bacteria during collection. Blood is collected into sterile blood collection packs which also include devices to improve safety, such as a sample pouch that prevents the tiny piece of skin from the needle and the first few drops of blood getting into the pack. These packs also facilitate the production of various blood components within a "closed" system thus significantly reducing the possibility of any bacterial contamination during processing. Further processing includes the filtration of blood to remove white cells from the blood, this being an additional precautionary safety measure.

Beyond the blood components produced locally in NIBTS, plasma products are produced by a number of appropriately licensed plasma fractionators and supplied to Northern Ireland's hospitals. The plasma used to produce such products is obtained from donors in a similar fashion to that described above from countries outside the UK as required by recent Government directives relating to BSE/vCJD. In addition plasma products undergo additional testing, pasteurisation and viral inactivation procedures before being released for issue.

Testing

You may have noticed that each time you give a blood donation we also take blood samples. These samples are used to perform a range of screening tests in our laboratories. Most of these tests are mandatory, in other words we must carry them out on every single blood donation, whether this is your first donation or just one of the many you have given over the years. The tests play a very important role in ensuring that we provide a safe blood supply to patients. We test for your blood group, so that we can select the correct group for the patient. We also test for infections that can be passed from donor to patient via a blood transfusion. Any donation that is reactive to any one of the mandatory screening tests cannot be used. If your blood is reactive on any one of the screening tests, further tests are carried out to confirm whether the result indicates a true infection. If this is the case, we will inform you and offer you appropriate advice. If the result is significant to your health you will be asked to discuss the results with one of our clinical staff and, with your permission, we will arrange a referral to your own doctor or a specialist. If the test results show that you can no longer give blood, then you will be given specific advice.

As well as checking your blood group, we test for the following infections:

  • Syphilis is caused by a bacterium called Treponema pallidum. This family of bacteria can also cause tropical diseases called Yaws and Pinta. Syphilis is usually a sexually transmitted infection which, if untreated, can cause serious disease. Yaws and Pinta cause skin and joint problems. All three diseases are fully treatable with antibiotics. The tests we use look for specific antibodies to the bacterium. These antibodies remain in a person's blood many years after the infection has gone. A positive test for syphilis often relates to an infection in the past, but we are not able to use blood as long as the test is positive.
  • Hepatitis B virus (HBV)is one of several viruses that can cause inflammation of the liver (hepatitis), and sometimes liver damage. Hepatitis B is very common in many parts of the world where it is often transmitted from mother to child at birth or in infancy. Most donors we identify have an association with these areas of the world and appear to have been infected since childhood or in early life. We do two tests for the virus; one looks for a marker called hepatitis B surface antigen, which is part of the 'coat' of the virus; and the second looks for the virus itself, targeting the virus nucleic acid. If we find surface antigen and/or the virusnucleic acid in a donor's blood then further tests are performed to confirm the result. Many of the donors we identify have been infected with the virus for years and are completely well. Sometimes we find a donor with new (acute) hepatitis B infection. Most adults who get hepatitis B have a short illness and overcome the infection. Occasionally we get a positive result in our hepatitis B test because the donor has recently had an immunisation against hepatitis B and not because infection is present. In some circumstances, such as skin piercing, where there is extra risk of getting hepatitis B due to reusable needles, we carry out extra tests to see if you have ever had hepatitis B infection.
  • Human immunodeficiency virus (HIV), if untreated,affects the immune system with the development of Acquired Immune Deficiency Syndrome (AIDS). The HIV virus is transmitted sexually, can be passed from mother to baby, and by intravenous drug use. Once an individual becomes infected with HIV, the virus remains in the body. A person who has HIV does not necessarily have AIDS. We perform two tests for the virus; one is a combination test that looks for both a protein in the virus coat and antibody to the virus; and a second that looks for the virus itself, targeting the virus nucleic acid. If either or both of the tests are reactive, further tests are done to confirm the result. Unlike many other infections the antibodies produced do not protect against the virus.
  • Hepatitis C virus (HCV), like hepatitis B, infects the liver and can cause inflammation and liver damage. The virus is commonly transmitted by needles, and thus may be associated with injecting drug use. Like HIV, HCV can persist in the body even when antibodies are present. We perform two tests for the virus, one that looks for antibody to the virus, and a second that looks for the virus itself, targeting the virus nucleic acid. If either or both of the tests are reactive, further tests are done to confirm the result. Like HIV, the antibodies produced do not protect against the virus. Many of the donors we identify have had the virus for years and feel completely well.
  • Hepatitis E Virus (HEV) can infect both animals and humans. HEV infection usually causes no symptoms but if it does, it generally produces only a mild inflammation of the liver, hepatitis E. Normally the virus infection will clear by itself. However, it is known that patients whose immune system is suppressed (eg chemotherapy or transplant patients) cannot clear the virus themselves and most will develop a persistent infection which may lead to chronic inflammation of the liver. You will be informed if the virus is found in your donation, even though it will be short-lived, in case you start developing any signs of illness.
  • Human T-lymphotropic virus (HTLV); a virus which infects white cells called T-lymphocytes. Like HIV, the HTLV virus remains in the body once an individual is infected, even though antibodies develop. Most people who are infected with the virus are perfectly well and never have any illness. Occasionally, it can cause a neurological disorder called Tropical Spastic Paraparesis (or HTLV Associated Myelopathy) or a blood disease called Adult T-cell Leukaemia. These diseases are very rare. The infection is found most commonly in people from Japan, the West Indies and parts of the Middle East. The virus is commonly transmitted from mother to child by breast feeding, but is also passed on by sexual contact or by intravenous drug use. We screen for antibodies against HTLV, and if the test is reactive further tests are performed to confirm the result.

Additional tests

Some tests are not performed on every donation. We may need to carry out additional tests depending on the donor's individual circumstances, in particular with reference to travel or skin piercing. Extra tests are also done to provide specifically tested blood for particular types of patient.

  • Malaria is caused by parasites which are transmitted by the bites of mosquitoes. The infection causes fever and is a major cause of death in some parts of the world. We test for antibodies to the malaria parasites. A confirmed positive result does not necessarily mean that the individual has active malaria, merely that they have had malaria at some time.
  • T-cruzi is a parasite called Trypanosoma cruzi, found in certain parts of Central and South America. It is transmitted to humans by biting insects or from mother to baby at the time of birth, or by blood transfusion. Over many years, the parasite can cause damage to the muscles in the heart and intestines, leading to an illness called Chagas disease. Not all infected people become ill. Our tests look for antibodies to the infection. A donor's place of birth and travel history determine whether the test is required.
  • Cytomegalovirus (CMV) is a very common virus which causes a mild 'flu-like' illness. Individuals in good health make a full recovery and are usually unaware of the infection. We may test for antibodies against the virus. A positive test indicates that the individual has had CMV infection and may still have the virus. Having antibodies to CMV is of no significance to the health of the donor. However, for patients with a poor immune system (bone marrow recipients or small babies), CMV can cause a life-threatening illness. CMV-positive blood is safe for most patients, and donors are not informed of a positive result.

Non-specific reactions

Any blood sample can give a reaction in laboratory screening tests, which on further testing proves to be non-specific. Non-specific reactivity can be found in all biological tests. Whenever we obtain a reactive screen result we carry out additional testing to determine whether the reactivity is non-specific or true reactivity due to infection. Non-specific reactivity is of absolutely no significance for the health of the donor, but unfortunately may affect the eligibility of some individuals to donate: if blood samples show such reactivity it may not be possible to use the blood. If this happens to you, you will be informed.

This range of tests is under regular review and additional tests may be introduced in the future.

Storage

All blood, blood components and plasma products are stored within predefined conditions which assure the maintenance of the quality and hence safety.

Distribution to Hospitals

When a hospital requests blood, blood components or plasma products our computer system, PULSE checks that there are no recorded reasons to doubt the safety of that component etc. PULSE also records where which hospital has received each component or product. This is facilitated by the application of unique donation identification numbers to all packs, samples and documentation at the time of collection and detailed tracking of these using PULSE.

At your local hospital

When you receive blood, blood components or plasma products, the laboratories will, where appropriate, have carried out tests e.g. patient blood grouping, and matching the donor cells against this recipient, to ensure as far as possible compatibility.