Title: SoGAT XVII, Paris, Paris 2004
1SoGAT XVII, Paris, Paris 2004
B19 Overview of Testing for Blood Banks
W. Kurt Roth Red Cross Blood Transfusion Service
Baden-Württemberg Hessen, Institute Frankfurt
am Main
2Parvovirus B19-PCR Testing Strategy
- Quantitative real-time TaqMan PCR
- Internal control sequence
- 3 external quantitative standards 106, 105, 104
IU/ml on each plate - External standards are spiked in negative plasma
- Routine donor screening on pools of 96
- Testing in parallel with HCV, HIV, HBV, HAV
- Testing for all blood components incl. red cells
and platelets - No exclusive and no delayed testing for source
plasma - 95 detection limit 103 IU / ml
- Decision level ? 105 IU / ml
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6Parvo B19 Positives per Month
Positives 105 (n)
7B19 positives in March - April 2004
sensitivity n donations n positive donations positive donations rate n pools n positive pools positive pools
105 72,972 23 0.03 1 3,173 902 19 2.1
103 72,972 130 0.18 1 561 902 130 14.4
105 68,147 25 0,04 1 2,726 883 23 2.6
103 68,147 139 0,20 1 490 883 139 15.7
March
April
Indicates at least 1 donation/pool
8Parvovirus B19-PCR Decision Making
- B19 positive Pools ? 105 IU / ml
- Positive donation identified
- Positive donation destroyed
- No donor deferral
- No donor information or counseling
- Reentry after donor tests PCR-negative (detection
limit lt 100 IU/ml) - B19 weak positive Pools lt 105IU / ml
- Positive donation not identified
- All donations released (weak positive for blood
bank software) - No labelling of product as B19 weak positive
- Parvo B19-negative and weak positive (gt 103 lt
105 IU / ml) components for all patients at no
specific risk - standard quality
9Indications for B19-negative components
- Parvo B19-negative (lt 103 IU / ml) components
upon specific written request individual label
Parvovirus B19 not detectable - Patients with BMT, SCT
- B19 antibody-negative pregant women in the 1.and
2. trimenon - HIV patients
- Additional risk groups e.g.
- transient aplastic crisis
- pure red cell aplasia
10The Netherlands approach Cellular components
- B19 virus safe cellular products to risk groups
only - Pregnant women
- Patients with congenital or acquired haemolytic
anemia who have no antibodies - Patients with cellular immunodeficiency who have
no antibodies - Safe products are
- IgG antibodies against B19 in two separate blood
samples, one taken at least six months after the
other. - To be introduced in 1st of July 2004
- To be introduced for quarantine plasma in April
2005
11The Netherlands Approach Plasma Products
- All products derived from pooled plasma
- Highly infectd donations should be identified and
removed before the individual sampkles are
pooled. - For final pools the maximum permissible limit is
104 genome copies of B19 per millilitre. - NAT for pools of 480 (10 x 48)
- one central facility ín Amsterdam.
- minipool NAT for HCV and HIV pools of 48 at 4
test centers.
12The future approach?
- B19 PCR and Ab testing on all donations
- Release PCR-only negatives and PCR negatives/Ab
positives - PCR negative/Ab positive products for patients at
risk and source plasma - Discontinue PCR and Ab testing for repeat
PCR-negatives/Ab positives - Continue PCR and Ab testing for first-time
donors, antibody negative and PCR positive
donors.
13Parvo-B19 Seroconversion
Medac IgM and IgG ELISA Mikrogen IgG/IgM
recomBlot