The use of blood has greatly increased during the past 25 years. One of the most important advances during this period is related to the development of methods of isolating, concentrating and storing the individual components of blood for specific clinical requirements. Along with this, new problems in science and technology, blood-donor organisation and medical care and the recruitment and training of staff have emerged. The opinion is advanced, that in the future, the efficiency of blood transfusion lies in its establishment as a separate discipline.

One unit of donor blood may be used to treat several patients. Each recipient is given the appropriate blood component. Proper component therapy is more effective and less hazardous than whole blood transfusion. In addition, valuable human blood is conserved.

Transfusion services require facilities to process fresh blood and separate otherwise labile components such as cryoglobulin precipitate and platelet concentrates. The production of large amounts of these components and of fractions such as plasma protein solution is facilitated by the clinical use of concentrated red cells rather than whole blood. Recurrent shortages of fresh donor blood are inevitable. Components which can be preserved for long periods should be stockpiled.

Plasmapheresis, plateletpheresis and leukapheresis allow the frequent collection of selected components from individual donors. Some of these donors may be hyperimmunised by the injection of an appropriate immunogen, and a specific immunoglobulin IgG can be prepared from the donated plasma. Hazards such as wrong identification and protein depletion must be avoided by individual attention to plasmapheresis donors.

Automation and modern transportation may increase the availability of blood. The importance of the blood donor to the health service and to the community should be fully recognised.

‘Selective transfusion of appropriate blood components is preferable to the routine use of whole blood.’ (American Association of Blood Banks. Physicians' Handbook of Blood Component Therapy, 1969).

The rational use of donor blood in the environment of modern blood transfusion revolves around a series of developments in the field of component therapy. The fractionation of plasma, i.e. the separation of plasma into a series of subdivisions each containing one or other of the constituent proteins in varying degrees of purity and concentration, was one of the first of these developments to become established.

Early fractionation of plasma was applied in various ways to the purification of animal antisera; initially to antipneumococcal serum for therapeutic use. These sera frequently provoked reactions in patients until Sabin showed that absorption with Fullers earth could abolish these side-effects by removing complexed molecules.

In 1967 when Tullis opened a discussion on ‘Methods and standards of blood transfusion’ he said that the discovery of citrate, which made it possible to store blood for a few days before transfusion, was perhaps the worst step that ever took place, because it made it possible for clinicians to abuse blood. Now they could collect it in a bottle, put it in a refrigerator for a few days and fully inactivate many labile components such as platelets, anti-haemophilic globulin, leucocytes and lipoproteins [1].

When blood is stored prior to transfusion there is a deterioration in the viability of the red cell in addition to other components. This has been assessed mainly on the post-transfusion survival, but in recent years more interest has been shown in the oxygen-carrying capacity.

If the organisers of this Symposium had invited our colleagues in the pharmaceutical industry to outline their concepts of efficiency, it is probable that two quite separate areas of endeavour would have emerged. In the first place, emphasis would have been made of efficiency in terms of technology, use of manpower and the production of profitable and useful by-products. In the second place, as the result of clinical trials, the persuasive Clinical Advisors would define the type of patient likely to benefit from their preparations, the correct dosage and the possibility of untoward effects. It is these broad aspects of effectiveness and safety which I wish to discuss in relation to blood transfusion, set against the fundamental question: what we are doing with our raw material at the present time and what awaits us in the future?

When one has spent—or mis-spent—substantial fractions of many years in gathering materials for a study and has eventually seen the results published in book form one is strongly conscious of a need to forget; at the very least there is a wish not to live in repetitious ways. An ancient Arab proverb, possibly relevant here, runs something like this: the word you have spoken is your master; the word you have not spoken is your slave. And so it is with my book The Gift Relationship which I sub-titled From Human Blood to Social Policy.

(1) Factor VIII preparations in the treatment of haemophilia and von Willebrand's syndrome. It should be appreciated that despite the recognition of many genetically determined coagulation defects, haemophilia is the only relatively common hereditary coagulation defect. The incidence is of the order of 1 per 20 000 of the population. Although relatively rare, the severe haemophiliac has so many problems that relevant therapeutic issues impinge more frequently on the physician than the incidence rate would indicate. These preparations also have a role in the rarer disorder of von Willebrand's syndrome, which is a genetically determined haemorrhagic state characterised by a prolonged bleeding time and often by a deficiency of factor VIII.

Plasma is used in the treatment of these conditions either as whole plasma or as one of its fractions —a simple prepared fraction called cryoprecipitate or as a lyophil dried preparation made by much more sophisticated and expensive techniques.

(2) Consideration must also be given to factor IX in the treatment of haemophilia B or Christmas disease.

In some ways this is easier to treat while in others it is more difficult. It is easier in the sense that factor IX is much less labile than factor VIII, but cryoprecipitate does not contain therapeutic amounts of factor IX and there is no equivalent simple fractionation procedure for factor IX. The ‘purified’ fractions are prepared by relatively more sophisticated and expensive techniques.

(3) In the management of vitamin K deficiency, oral anticoagulant therapy or liver disease then purified preparations of factors II, VII, IX and X may be required.

(4) In the defibrination syndrome fibrinogen may be needed.

Although active immunisation against infection tends to diminish the usefulness of immunoglobulin a return to passive immunisation may well occur because of the public apathy regarding childhood immunisation schedules, the development of antibiotic resistance and the expanding proportion of patients who are infection prone because of immunosuppression. An assessment of the usefulness and likely demand for immunoglobulin is urgently needed. It does not transmit infection and it is generally free of side-effects when a single dose is injected. Human normal immunoglobulin prevents infectious hepatitis (virus A) and measles and is valuable for hypogammaglobulinaemic patients. Limited supplies of human specific immunoglobulins are available and effective in preventing Rhesushaemolytic disease, in treating the complications of smallpox vaccination, and for tetanus prophylaxis. Hyperimmune material may also become available for the prevention of serum hepatitis (virus B), chickenpox and the rubella syndrome. Problems of administration and supply could prove difficult to overcome. The principles involved in preventing Rhesus-haemolytic disease with immunoglobulin could possibly be applied in the management of auto-immune disease at some future date.

Plasma fractionation has provided a number of materials which may be used to treat conditions in which whole blood would be of little or no value. It was in 1944 that Cohn and his co-workers published a series of papers on plasma fractionation (Cohn et al. 1944) and in the same year Janeway and his colleagues first suggested the use of albumin in hypoproteinaemic states (Janeway et al. 1944). Since then many accounts of the treatment of generalised oedema have mentioned the employment of salt-poor albumin as an adjunct to therapy (Chamberlain et al. 1966; Garnet and Webber 1967; Silverberg and Kjellstrand 1968; Snashall 1971), but no attempt has been made recently to evaluate the place of albumin in such patients.

The Blood Transfusion Service has an important role to play in organ transplantation in finding and classifying typing reagents for histocompatibility testing. The development of banks of frozen blood is of importance in reducing the incidence of sensitisation to HLA antigens and the hazard of posttransfusion hepatitis.