Safe Blood

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Safe Blood

  1. 1. Safe Blood; Facts, Challenges and Future Directions Dr. Saba Jamal Ziauddin University Hospital
  2. 2. Facts <ul><li>Advances in infectious disease testing continue to improve the safety of blood supply </li></ul><ul><li>However viral, bacterial & parasitic disease can still be transmitted by transfusions </li></ul><ul><li>Novel infectious agents may also appear at any time eg. HIV in the 1980’s </li></ul>
  3. 3. International Standards For Screening of Blood
  4. 4. Hepatitis B - Virus <ul><li>Markers of infectious screening; HBsAg, Anti- HBc Total </li></ul><ul><li>Methodology; - ELISA ( recommended), </li></ul><ul><li>detects approx. 0.2-0.7ng/ml HBsAg or >3x10 7 particles </li></ul>
  5. 5. Rationale for Anti-HBc Testing <ul><li>Early convalescent phase acute HBV infection </li></ul><ul><li>Low level chronic HBV/tail-end infection </li></ul><ul><li>Mutants </li></ul><ul><li>Will not detect pre-seroconversion window period </li></ul>
  6. 6. Hepatitis C - Virus <ul><li>Markers of infection ; Anti-HCV, HCV RNA </li></ul><ul><li>Window Periods ; - Anti – HCV by Third Generation ELISA/EIA; 70 – 80 days - NAT; 10 – 30 days </li></ul>
  7. 7. Human Deficiency Virus (HIV) ELISA/ EIA is the test of choice for Anti HIV 1 & 2 <ul><li>20- 25 days </li></ul><ul><li>16 days </li></ul><ul><li>11 days </li></ul><ul><li>Anti- HIV 1 & 2 </li></ul><ul><li>p24 antigen </li></ul><ul><li>NAT Testing </li></ul>Window Periods Markers of infection
  8. 8. SYPHILIS <ul><li>Phase of spirochetemia is brief & organisms survive only 4 days at 4 o C </li></ul><ul><li>Performance of serologic test for syphilis is still a requirement </li></ul>
  9. 9. Malaria <ul><li>Asymptomatic carriers with very low parasite load are generally the source of transfusion - transmitted malaria </li></ul><ul><li>Tests available; - Screening by smears - Serologic Testing for malaria antigen or LDH - PCR </li></ul>
  10. 10. Malaria <ul><li>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 </li></ul><ul><li>- PCR; Shows promise but cost is the issue </li></ul>
  11. 11. Bacterial Contamination; <ul><li>Yersinia enterocolitica, </li></ul><ul><li>Serratia Liquifaciens, </li></ul><ul><li>Staphylococcus, </li></ul><ul><li>Enterobacteriaceae, </li></ul><ul><li>Streptococcus, </li></ul><ul><li>Bacillus, </li></ul><ul><li>Psuedomonas </li></ul>
  12. 12. Infectious Risks of Blood Transfusion in the United States <ul><li>HBV </li></ul><ul><li>HCV </li></ul>1:1,900,000 1:63,000 1:1,600,000 <ul><li>RBCs </li></ul><ul><li>Platelets </li></ul>1:1,000 1:2,000 <ul><li>Malaria </li></ul><1:1,000,000 Infectious agent or outcome Estimated Risk per Unit transmited <ul><li>HIV-I&2 </li></ul>Virus Bacteria Parasite
  13. 13. Screening Performed in Pakistan <ul><li>HBsAg </li></ul><ul><li>Anti-HCV </li></ul><ul><li>Anti- HIV 1 & 2 </li></ul><ul><li>Malaria </li></ul><ul><li>Syphilis </li></ul>
  14. 14. Challenges in Pakistan <ul><li>Absence of screening in certain centers </li></ul><ul><li>Substandard Methods of screening eg. Latex based, sub-standard ELISA </li></ul><ul><li>Pooling of Donor Sera; - Increases the risk of transmission. Bigger the pool, higher the risk </li></ul><ul><li>Anti-HBc Total Antibody & NAT testing for HCV & HIV ; NOT PERFORMED </li></ul>
  15. 15. Future Directions <ul><li>Across the board implementation of infectious disease screening by Standard ELISA methods </li></ul><ul><li>Minimize residual risk of transfusion-transmitted viral infections </li></ul><ul><li>Motivate young healthy volunteer donors </li></ul><ul><li>Awareness of Physicians as well as the patients in risks of transfusion transmitted diseases </li></ul>
  16. 16. Thank You

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