# Presentation: 209851

## Laboratory Support Challenges forBlood Transfusion Safety

## Relevance of Blood Transfusion Safety Activities

- Approximately 90 million transfusions worldwide annually
- 31% of transfusions not screened for HIV, Hepatitis B or Hepatitis C
- Most laboratory screening lapses occur in developing countries

- Source: WHO, GDBS 2001

## Relevance of Blood Transfusion Safety Activities 

- Annually, unsafe blood transfusions are estimated to be responsible for
- 10,000 new HIV infections
- 78,000 new HBV infections
- 500,000 new HCV infections

## Conditions Requiring Transfusions in Developing Countries

- Acute malarial anemia
- Nutritional anemia or intestinal helminth infection
- Obstetric-related anemia or hemorrhage
- Accidents
- Surgery
- Thalassemia or Sickle-Cell Anemia

## Ideal Blood Safety Program

- Assist countries with development of national blood transfusion policy
- Build or strengthen infrastructure for regionalization blood collection centers, allowing hospitals to become transfusion centers, not blood collection centers
- Increase the supply of low-risk volunteer donors

## Ideal Blood Safety Program (Cont’d)

- Test 100% of the blood supply for the most important transfusion-transmitted infections (TTI) - HIV, HBV, HCV and syphilis
- Help decrease the demand for transfusions through development of clinical guidelines
- Help develop systems for strong laboratory oversight, quality assurance and management
- Use only disposable equipment

## Example of GAP-supported Blood Safety Activities - Kenya

- NBTS policy already in existence
- Provided technical assistance for development of regional transfusion centers
- Assisted with implementation of  universal testing for HIV, HBV and syphilis.
- Established training fellowship for physicians
- Developed clinical guidelines for transfusion practice
- Assisted in development of QA system

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## Tests for Transfusion-transmitted Infections

- Universally required screening
- HIV antibody
- HBSAg
- Syphilis
- Suggested screening when determined appropriate
- HCV antibody
- Malaria
- T. cruzi antibody

## Estimated Laboratory Screening Rates of Blood Donors in Africa

- 				1999		    2002
-      HIV		 75%	              90%
-      HBV		 50%		     55%
-      HCV		 19% 	     40%

- Source: WHO, AFRO 2003

## Additional Laboratory Tests Performed in Support of Blood Transfusion Safety 

- Traditional blood banking tests
- ABO grouping, Rh typing and Crossmatch
- Antibody screening
- Diagnostic hematology tests
- Hemoglobin, Hematocrit, and Platelet count
- Coagulation tests
- Prothrombin time and Partial Thromboplastin time

## Perception of Blood Safety in Developing Countries

- The common view of blood safety in developing countries is simply screening blood for HIV.
- The ability to perform an HIV screening test should not be viewed as a license to perform transfusions.
- Must consider the serious risks of transfusion, as well as the benefits.

## Risks of Adverse Events from Transfusion are Significant

- TTI such as HBV and HCV infection
- Sepsis
- Hemolytic transfusion reaction

## Residual Risk of TTI After Screening

- Residual risk of transfusion-transmitted HIV infection may be 2%, even after testing.*
- Sources of residual risk
- Failure to test
- Human  error (mislabeling, procedural)
- False negatives (equipment and reagents)
- Window period donations

- * (Moore, et al., 2001)

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## Combined Approach to Blood Donor Screening

- Blood centers employ  a combination of strategies to protect the blood supply, including pre-donation risk deferral questions and laboratory screening tests.
- Risk deferrals are most effective in localized epidemics.
- Pre-donation questions are less effective when a behavior or risk is common to most of the population, i.e., heterosexual sex.
- Therefore, in developing countries there is a heavier reliance on laboratory-based screening methods.

## Blood Transfusion Safety and the Clinical Laboratory

- Traditionally, blood transfusion practice and blood banking are part of the larger clinical laboratory
- Involve both laboratory practice and medical care

## Challenges for Laboratory Support

- Standardization of laboratory operating procedures
- Standardization of equipment and reagents
- Assist with development of quality management systems and quality management training
- Assist with reference laboratory support
- Assist with data management