[A retrospective study of the practice of "look-back" procedures, on the incidence of HIV-1/2-positive blood donors and the risk of transfusion-associated HIV infection in public-community blood banks in Germany].

OBJECTIVE

'Look-back' investigations can reveal and confirm transfusion-transmitted infectious diseases and provide data for risk calculations of blood transfusions.

DESIGN

In 1993 we distributed a questionnaire to all governmental and communal blood transfusion services in Germany. The questionnaire comprised questions about the methods, numbers and results of look-back investigations in case of HIV-1/2-positive blood donors with previous donations and in case of HIV-1/2-positive recipients of blood transfusions. The questionnaire was returned by almost all blood transfusion services (n = 75). One additional institution briefly informed us by telephone.

SETTING

All governmental and communal blood transfusion services in Germany.

PATIENTS

All recipients of blood or blood products in the years from 1985 till the end of 1992 who were treated in hospitals supplied by the transfusion services defined above.

INTERVENTIONS

None.

RESULTS

All blood transfusion services included have performed look-back studies since 1985. The methods used varied considerably. The interval of looking back mostly was sufficient. A main problem was the poor documentation in the medical records. The incidence of HIV-1/2-positive blood donations decreased from 11.6/100,000 in 1985 to 3.4/100,000 in 1992. Only 7 of 73 transfusion-transmitted HIV infections derived from transfusions after the introduction of HIV testing (October 1985). Since then the risk of transfusion-transmitted HIV infection can be calculated as 1/800,000 whole-blood donations of governmental and communal blood transfusion services.

CONCLUSIONS

Since the introduction of HIV testing the risk of transfusion-transmitted HIV infection in Germany has been very low, at a rather stable rate of 1/800,000. The data from the look-back studies confirm the previous estimations of the risk of transfusion-transmitted HIV infections, which was calculated by the HIV incidence in the donor population. Nevertheless there is a need for standardization of look-back investigations.