ADVANCES IN BLOOD SAFETY: A NEW ERA IN BLOOD TESTING TECHNOLOGY

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ADVANCES IN BLOOD SAFETY A NEW ERA IN BLOOD
TESTING TECHNOLOGY

• Dr A Bird 2005

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NATIONAL BLOOD POLICY

• Selection of low risk blood donors
• The national policy recognises that it is
  essential to select low risk blood donors. This
  is particularly so given the limitations of
  current test systems to identify the diseases
  that may be transmitted by transfusion
• Selection of donors is by
• obtaining blood only from voluntary
  non-remunerated donors
• recognising that it is inherently dangerous to
  collect blood from communities with a high
  prevalence of disease that may be transmitted by
  transfusion. This information must not be used
  to stigmatise and discriminate in, or against,
  the community
• collecting epidemiological information to
  develop appropriate criteria for exclusion of
  donors who are recognised as a high risk for
  transmitting disease by donating blood

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BLOOD SAFETY/RISK MANAGEMENT DONORS

• Voluntary non-remunerated donors
• Emphasis on regular donations
• Self-exclusion of donors
• Education and pre-donation information
• Donor questionnaire
• Donor interview
• THIS PROCESS SEEKS TO IDENTIFIFY DONORS WHO ARE
  NOT AT RISK FOR HIV INFECTION

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BLOOD SAFETY/RISK MANAGEMENT PRODUCT

• All individual donations tested for
• HIV 1 2 abs
• HIV p24 ag
• HCV abs
• HBsAg
• Syphilis

• Limiting number of products from one donation
• Quarantine plasma

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BLOOD SAFETY/RISK MANAGEMENT PATIENT

• Education/training
• Right product
• Right patient
• Right indication
• Informed consent
• Look back programme
• Haemovigilance programme

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HIV PREVALENCE WESTERN CAPE
Comparison General Population vs Blood Donors
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End Aug 2005
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• In 1999 SANBS (then SABTS NBTS) introduced
  risk categorisation largely based on race
• WPBTS did not follow suit while scientific
  basis was rational it was felt that it would not
  be acceptable to the population at large
• Risk profiling based on racial profiles regarded
  as unacceptable by the DoH (Dec 2004)
• Discussions with DoH result in decision to
  approach risk management from a different
  perspective
• Introduction of more sensitive tests namely
  genomic amplification or nucleic acid
  amplification technology cost implications
• Possible exclusion of first time donors use
  for plasma derivatives only supply implications
• Implementation of NAT by October 2005
• Will investigate exclusion of first time donors
  but serious concerns re supply impact and
  motivational sequelae for first time donors

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NUCLEIC ACID AMPLIFICATION(NAT) TECHNOLOGY

• NAT essentially enables us directly to detect
  the viral genome (RNA or DNA) unlike current
  methodologies which rely on detection of proteins
  (antigens and antibodies) produced in response to
  infections and which are less sensitive
• NAT technology has been around for a decade or
  more but until recently was largely a research
  tool and unsuitable for individual donor
  screening which requires automation and rapid
  throughput

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• Genomic screening can be performed with several
  nucleic acid amplification technique
• Polymerase chain reaction (PCR)
• Ligase chain reaction (LCR)
• Nucleic acid sequence-based amplification
• Transcription mediated amplification (TMA)
• Main principle is the ability of the technology
  to amplify nucleic acid sequences (DNA or RNA)
  specific to the micro-organism from very small
  quantities into billions of copies

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Procleix TMA-Based Assays
Detection of Multiple Viruses in a Single Tube

• Target Capture
• Selective capture of viral specific nucleic acids
  on magnetic particles
• Internal Control (IC) Included
• Transcription-Mediated Amplification (TMA)
• Amplifies target region of the nucleic acids
• Dual Kinetic Detection
• Hybridization Protection Assay (HPA) inactivates
  unhybridized probes to minimize background
• Dual Kinetic Assay (DKA) simultaneously detects
  IC and viral RNA or DNA signal

HIV HCV HBV
Magnetic microparticle
IC
HIV HCV HBV IC
Amplified RNA
HIV-1 HCV HBV IC
Dual Light Emission
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NAT Reduces Window of Detection
1.J Linnen et al. Effect of Donor Mini-Pool Size
on Closure of the Hepatitis B Virus (HBV)
Donation Window A Comparison of Triplex TMA to
Surface Antigen Detection. Poster presentation.
ISBT 2002 Vancouver, BC August 24-28, 2002 2.
Package Insert for the Procleix HIV-1/HCV Assay,
IN0076.l