THE national blood supply remains safe despite a recall of some chemicals used to test donated blood for the human immunodeficiency virus (HIV) and the hepatitis B and C viruses, the Health Sciences Authority (HSA) has said.
No tainted blood sample would have slipped through and be used undetected because all samples would also have been put through another test using chemicals unaffected by the recall, it added.
This other test is a compulsory standard for all international blood service providers, whereas the test using the affected batches of chemicals was an optional one used as 'an additional safeguard', it said.
Chiron, the manufacturer of the chemicals - called reagents - voluntarily recalled some batches of its product last Friday. The affected batches had, since last November, been stored in a warehouse where a freezer has been found to have an inconsistent temperature.
The warehouse was not run by Chiron.
Its spokesman Eric Althoff said: 'No reports of injury or adverse events related to the use of these implicated products have been identified.'
The recall, involving countries in the Asia-Pacific, was a precaution, and clients have been given fresh batches of reagents to replace the questionable ones, he said.
Mr Althoff was unable to give figures on the quantity of reagents recalled or the number of laboratories affected here, saying that details were still being collated.
From last December to early this month, the HSA had used some of these batches of reagents to carry out one of the two tests on all samples of donated blood to check for the HIV and hepatitis B and C viruses.
It declined to reveal the quantity of reagents and tests involved.
It is unclear if the quality of the reagents was compromised by fluctuations in storage temperatures beyond the recommended -15 to -35 deg C.
Chiron has been testing the batches in question to determine this. So far, it has found that those used within 12 days of being thawed worked normally.
It will continue to test the questionable batches to see if they work up to 30 days after being thawed - their usual shelf life.
The HSA said that 99 per cent of the blood donations it received since last December had been tested using reagents that had been thawed for up to 12 days.
The rest had been tested with reagents that had been thawed for up to 22 days.
The HSA's quality-control checks also showed that test results obtained during this period were consistent with its own previous results and with results from other labs using unaffected reagents.
There has therefore been no evidence that the safety of donated blood has been compromised, the HSA said. It collects blood from volunteer donors, enforces stringent criteria, runs a battery of tests and has a strong quality-control system.
Dr Diana Teo, group director of the HSA's blood services group, said that 'multiple firewalls' were in place, and added: 'We have always placed the highest priority in ensuring that our blood supply is as safe as possible.'
This article was first published in The Straits Times on August 23, 2008.
