International standards for screening blood donations require testing for hepatitis B, hepatitis C, HIV, syphilis, and malaria. While screening has improved blood safety, risks remain as new infectious agents may emerge and current tests have window periods where early infections are not detected. In Pakistan, screening is not uniform across centers and some use substandard methods, like pooling donor samples, which increases transmission risk. Future directions include fully implementing standard screening tests, minimizing residual risks through new tests, encouraging healthy volunteer donors, and increasing awareness of transfusion risks.

1. Safe Blood; Facts, Challenges and Future Directions Dr. Saba Jamal Ziauddin University Hospital

2. Facts Advances in infectious disease testing continue to improve the safety of blood supply However viral, bacterial & parasitic disease can still be transmitted by transfusions Novel infectious agents may also appear at any time eg. HIV in the 1980’s

3. International Standards For Screening of Blood

4. Hepatitis B - Virus Markers of infectious screening; HBsAg, Anti- HBc Total Methodology; - ELISA ( recommended), detects approx. 0.2-0.7ng/ml HBsAg or >3x10 7 particles

5. Rationale for Anti-HBc Testing Early convalescent phase acute HBV infection Low level chronic HBV/tail-end infection Mutants Will not detect pre-seroconversion window period

6. Hepatitis C - Virus Markers of infection ; Anti-HCV, HCV RNA Window Periods ; - Anti – HCV by Third Generation ELISA/EIA; 70 – 80 days - NAT; 10 – 30 days

7. Human Deficiency Virus (HIV) ELISA/ EIA is the test of choice for Anti HIV 1 & 2 20- 25 days 16 days 11 days Anti- HIV 1 & 2 p24 antigen NAT Testing Window Periods Markers of infection

8. SYPHILIS Phase of spirochetemia is brief & organisms survive only 4 days at 4 o C Performance of serologic test for syphilis is still a requirement

9. Malaria Asymptomatic carriers with very low parasite load are generally the source of transfusion - transmitted malaria Tests available; - Screening by smears - Serologic Testing for malaria antigen or LDH - PCR

10. Malaria Sensitivity for screening very low parasitic load i.e. asymptomatic carriers; - Smears, 20 parasites /ul - Serologic tests; No practical serologic tests available in asymptomatic donors - PCR; Shows promise but cost is the issue

11. Bacterial Contamination; Yersinia enterocolitica, Serratia Liquifaciens, Staphylococcus, Enterobacteriaceae, Streptococcus, Bacillus, Psuedomonas

12. Infectious Risks of Blood Transfusion in the United States HBV HCV 1:1,900,000 1:63,000 1:1,600,000 RBCs Platelets 1:1,000 1:2,000 Malaria <1:1,000,000 Infectious agent or outcome Estimated Risk per Unit transmited HIV-I&2 Virus Bacteria Parasite

13. Screening Performed in Pakistan HBsAg Anti-HCV Anti- HIV 1 & 2 Malaria Syphilis

14. Challenges in Pakistan Absence of screening in certain centers Substandard Methods of screening eg. Latex based, sub-standard ELISA Pooling of Donor Sera; - Increases the risk of transmission. Bigger the pool, higher the risk Anti-HBc Total Antibody & NAT testing for HCV & HIV ; NOT PERFORMED

15. Future Directions Across the board implementation of infectious disease screening by Standard ELISA methods Minimize residual risk of transfusion-transmitted viral infections Motivate young healthy volunteer donors Awareness of Physicians as well as the patients in risks of transfusion transmitted diseases

16. Thank You