sogat xvii, paris, paris 2004

Ro / BSD HessenInstitut für Transfusionsmedizin

SoGAT XVII, Paris, Paris 2004

B19 Overview of Testing for Blood Banks

W. Kurt RothRed Cross Blood Transfusion Service Baden-Württemberg – Hessen,

Institute Frankfurt am Main


Parvovirus 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


0

5

10

15

20

25

30

Parvo B19 Positives per MonthP

ositi

ves

105

(n)


B19 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

* Indicates at least 1 donation/pool

M

arch

A

pri

l


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 < 100 IU/ml) B19 „weak“ positive Pools < 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 (> 103 ; < 105 IU / ml) components for

all patients at no specific risk – standard quality

Parvovirus B19-PCR: Decision Making


Indications for B19-negative components

Parvo B19-negative (< 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


The 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


The 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.


The 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.


Parvo-B19 Seroconversion

Vorspende Spende Folgespende 2. Folgesp.Datum IgM/

GDatum Konz

ExpIgM IgG Datum Hs-

PCRIgM IgG Wb

NS1IgM Wb

NS104.07.00 - 17.01.01 12 - - 02.08.01 - + ++ +28.03.00 - 14.07.00 12 - - 15.02.01 - ? ++ ++28.02.00 - 20.06.00 11 - - 27.10.00 + ? ++ ? - +15.02.99 15.05.00 11 + - 06.08.00 + + ++ + - ++12.01.00 - 12.04.00 11 - - 05.07.00 + + ++ ? - ?15.01.01 - 16.03.01 8 + - 22.06.01 + - ++ +09.02.00 - 03.05.00 8 - - 09.08.00 + + ++ +30.11.00 - 30.03.01 8 + - 29.06.01 + + ++ +25.08.00 - 27.10.00 7 - - 26.01.01 + + ++ - ? -09.02.00 - 03.05.00 6 + ? 23.08.00 + + ++ ++ + +++19.01.00 - 10.05.00 5 ++ + 17.01.01 - + ++ +++02.04.01 - 02.07.01 5 ++ + 11.09.01 + + ++ +++

Medac IgM and IgG ELISA; Mikrogen IgG/IgM recomBlot

sogat xvii, paris, paris 2004

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