SINGAPORE — About 5,300 cord blood units stored in a second Cordlife tank and a dry shipper have been deemed "non-viable", the Ministry of Health (MOH) said on Monday (April 8).

This is on top of the roughly 2,200 cord blood units belonging to at least 2,150 clients that were damaged in the first tank.

Cordlife has been under scrutiny after it was revealed in November last year that several storage tanks were exposed to temperatures above -150°C, the acceptable limit for cord blood units. This was made public on Nov 30 when MOH said Cordlife was being investigated.

Besides the damaged cord blood units in the first tank, MOH had directed Cordlife to conduct further testing of six other affected storage tanks and a dry shipper, which is intended for transport and not for long-term storage.

"The results of the further investigations, which have been reviewed by MOH and its panel of experts, revealed that cryopreserved cord blood units stored in one of the storage tanks (Tank B) and the dry shipper are at high risk of adverse impact due to temperature warming events," said MOH on Monday.

"Hence an estimated 5,300 CBUs from Tank B and the dry shipper are deemed non-viable as they are unlikely to be suitable for stem cell transplant purposes."

MOH said the remaining five tanks have been assessed to be at low risk after being "adversely affected by the temperature warming events".

"MOH’s experts have recommended that Cordlife test a larger number of cord blood units in these five tanks to obtain a more statistically significant result and further ascertain the status of the cord blood units stored in these tanks," the ministry added.

Seven people have been arrested in connection with the case.

TEST RESULTS FOR TANK B, DRY SHIPPER

Audits conducted by MOH on Cordlife in August and November last year revealed that cord blood units in seven of its 22 storage tanks had been exposed to “suboptimal storage temperatures”.

MOH said that although the definitive way to conclude the viability of the cord blood units is to individually test all the units in the affected tanks, this was not practical.

It would take years “even decades”, to complete all the tests, it added.

Cordlife conducted sample testing through a third-party laboratory.

“This will provide a preliminary, but meaningful, indication if the warming events had impacted the CBUs stored in these tanks,” said MOH.

Eight out of 12 samples from the second tank, Tank B, failed the tests, as did five out of 12 samples from the dry shipper.

The study results and root cause analysis indicated that the cord blood units stored in Tank B and the dry shipper were at high risk of being adversely affected.

The root cause analysis indicated that there was insufficient liquid nitrogen maintained in Tank B, which had not been rectified due to the failure of Cordlife’s staff to act on and escalate the anomalies. The dry shipper had also not been adequately monitored, said MOH.

Given the findings, the 5,300 units in Tank B and dry shipper are “not likely to be suitable for stem-cell transplant purposes” and are deemed non-viable.

MOH has instructed the company to inform its affected clients if their cord blood units fall under Tank B or the dry shipper.

TEST RESULTS OF FIVE OTHER TANKS

The remaining five tanks, which store about 14,000 cord blood units, have been assessed through investigations to be "at low risk of being adversely affected by temperature warming events", said MOH.

All 30 samples from across the five tanks passed the viability and potency tests conducted by an independent third-party lab.

The root cause analysis indicated that the "temperature warming events" in four out of five tanks — Tanks D to G — were likely due to misplaced temperature probes during scheduled maintenance, or incorrect mapping of the temperature probe to the tank.

For Tank C, the duration of exposure to the highest temperature of -144.7°C might not have caused damage to the cord blood units, said MOH.

MOH experts have recommended that Cordlife test a large number of cord blood units in these five tanks to achieve more statistically significant results — 99 per cent of the samples tested must pass both potency and viability tests.

Cordlife has agreed to test more than 200 more samples across the five tanks and will review the outcome of the test results with MOH experts.

"As the tests, which involve complex processes, have to be carefully carried out, Cordlife expects to take approximately another year to complete the tests," said the ministry.

Cordlife has also been told to inform its affected clients if their units are in the five tanks that have a low risk of being affected, but are awaiting further tests.

"Affected clients of Cordlife are advised to be patient and await these results before making any decisions, including the transfer of cord blood units to another cord blood bank, given that there are significant risks involved in the transfer of cord blood units," said MOH.

"MOH will continue to closely supervise Cordlife’s rectification of the weaknesses identified in their governance structure, processes, systems and documentation." CNA