265 Vox Sanguinis (2005) 89, 265 LETTER © 2005 Blackwell Publishing Blackwell Publishing, Ltd. Oxford, UK VOX Vox Sanguinis 0042-9007 2003 Blackwell Publishing Ltd 89 4 265 LETTER Letter to the Editor Letter to the Editor LETTER Implementation of donor screening for infectious agents transmitted by blood by nucleic acid technology in Japan H. Yugi, S. Hino, M. Satake & K. Tadodoro NAT Department of Central Blood Institute, Japanese Red Cross, Tokyo, Japan Further to the international forum ‘Implementation of Donor Screening for Infectious Agents Transmitted by Blood by Nucleic Acid Technology: Update to 2003’ ( Vox Sang 2005 88: 289–393), we present here the results from Japan. The Japanese Red Cross Blood Center is the only institute in Japan that deals with blood procurement, processing, testing and delivery in the whole country. In October 1999, it imple- mented nucleic acid amplification testing (NAT) nationwide for hepatitis B virus (HBV) as well as for hepatitis C virus (HCV) and HIV utilizing the Roche multiplex primer reagent. The entire process from pooling to real-time polymerase chain reaction (PCR) is fully automated. Because the number of seropositive samples for HBV is so high in Japan, only seronegative samples are pooled, demanding the rapid com- pletion of serological testing at local blood centres. We have so far encountered no cases of cross-contamination between samples. Blood aliquots from all donations are sent to three NAT centres at midnight on the day of blood collection, and the NAT results are reported to all blood centres the following morning or afternoon. No components are released without confirming the NAT results in spite of the situation that platelet concentrates have an expiration time of 72 h after collection. After 7 months using the 500-minipool system, we moved to the 50-pool system in February 2000. In August 2004, we further decreased the pool size to 20 without altering the existing logistics and schedule. The increase in the yield of seronegative but NAT-positive donations was not evident for HIV and HCV as the pool size decreased, but is apparent for HBV, as confirmed by several donations that were 50-pool- NAT-negative but 20-pool-NAT-positive for HBV. This would be one of the theoretical bases for the implementation of NAT with a smaller pool size for HBV in a country like Japan where HBV infection is highly endemic. Around 90% of NAT-only positive blood samples are considered to be derived from window-period donations although a relatively high yield of NAT-only positive donations can be partly explained by the lower sensitivity of the HBsAg detection method we use (agglutination) than that of enzyme immunoassay (EIA) or chemiluminescent immunoassay (CLIA). As for serological HBV screening, we are currently using a combination of the HBsAg, HBcAb and HBsAb assays. While a donor with a low HBcAb titre is accepted, a donation with a high HBcAb titre is qualified only if its HBsAb titre is suf- ficiently high to induce a protective effect (> or = 200 m IU/ ml). Although the NAT system is a powerful tool for detecting window-period donations and often detects chronic carriers with a low HBV viral load and fluctuating viraemia, we have experienced a considerable number of minipool–NAT break- through cases where HBV infection occurred as a result of the transfusion of minipool–NAT-negative components or even individual donation NAT-negative components. Received: 19 July 2005, accepted 27 July 2005 H. Yugi ([email protected]) S. Hino ([email protected]) M. Satake ([email protected]) K. Tadokoro ([email protected]) NAT Department of Central Blood Institute Japanese Red Cross Nakarokugo 3-30-1 Oota-ku Tokyo 144–0055 Japan

Implementation of donor screening for infectious agents transmitted by blood by nucleic acid technology in Japan

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Page 1: Implementation of donor screening for infectious agents transmitted by blood by nucleic acid technology in Japan

265

Vox Sanguinis

(2005)

, 265

LETTER

2005 Blackwell Publishing

Blackwell Publishing, Ltd.Oxford, UKVOXVox Sanguinis0042-90072003 Blackwell Publishing Ltd894265LETTERLetter to the EditorLetter to the EditorLETTER

Implementation of donor screening for infectious agents transmitted by blood by nucleic acid technology in Japan

Yugi, S.

Hino, M.

Satake & K.

Tadodoro

NAT Department of Central Blood Institute, Japanese Red Cross, Tokyo, Japan

Further to the international forum ‘Implementation of DonorScreening for Infectious Agents Transmitted by Blood byNucleic Acid Technology: Update to 2003’ (

Vox Sang

200588: 289–393), we present here the results from Japan.

The Japanese Red Cross Blood Center is the only institute inJapan that deals with blood procurement, processing, testingand delivery in the whole country. In October 1999, it imple-mented nucleic acid amplification testing (NAT) nationwidefor hepatitis B virus (HBV) as well as for hepatitis C virus(HCV) and HIV utilizing the Roche multiplex primer reagent.The entire process from pooling to real-time polymerasechain reaction (PCR) is fully automated. Because the numberof seropositive samples for HBV is so high in Japan, onlyseronegative samples are pooled, demanding the rapid com-pletion of serological testing at local blood centres. We haveso far encountered no cases of cross-contamination betweensamples. Blood aliquots from all donations are sent to threeNAT centres at midnight on the day of blood collection, andthe NAT results are reported to all blood centres the followingmorning or afternoon. No components are released withoutconfirming the NAT results in spite of the situation that plateletconcentrates have an expiration time of 72 h after collection.

After 7 months using the 500-minipool system, we movedto the 50-pool system in February 2000. In August 2004, wefurther decreased the pool size to 20 without altering theexisting logistics and schedule. The increase in the yield ofseronegative but NAT-positive donations was not evident forHIV and HCV as the pool size decreased, but is apparent for

HBV, as confirmed by several donations that were 50-pool-NAT-negative but 20-pool-NAT-positive for HBV. This wouldbe one of the theoretical bases for the implementation of NATwith a smaller pool size for HBV in a country like Japanwhere HBV infection is highly endemic. Around 90% ofNAT-only positive blood samples are considered to be derivedfrom window-period donations although a relatively highyield of NAT-only positive donations can be partly explainedby the lower sensitivity of the HBsAg detection method weuse (agglutination) than that of enzyme immunoassay (EIA)or chemiluminescent immunoassay (CLIA).

As for serological HBV screening, we are currently using acombination of the HBsAg, HBcAb and HBsAb assays. Whilea donor with a low HBcAb titre is accepted, a donation witha high HBcAb titre is qualified only if its HBsAb titre is suf-ficiently high to induce a protective effect (> or = 200 m IU/ml). Although the NAT system is a powerful tool for detectingwindow-period donations and often detects chronic carrierswith a low HBV viral load and fluctuating viraemia, we haveexperienced a considerable number of minipool–NAT break-through cases where HBV infection occurred as a result of thetransfusion of minipool–NAT-negative components or evenindividual donation NAT-negative components.

Received: 19 July 2005,accepted 27 July 2005

H. Yugi ([email protected])S. Hino ([email protected])M. Satake ([email protected])K. Tadokoro ([email protected])NAT Department of Central Blood InstituteJapanese Red CrossNakarokugo 3-30-1Oota-kuTokyo 144–0055

Japan