A total of 233 Covid-19 swab samples were accidentally disposed of before they were tested, following lapses at a private medical lab.
The batch was collected from clinics under the Swab and Send Home (Sash) programme. The test samples were "inadvertently discarded prior to testing" at the lab, a spokesman for Quest Laboratories told The Straits Times yesterday.
Under the Sash programme, patients who meet certain criteria are swabbed and then sent home to wait for their test results. Their swab samples are sent to a lab, where testing can take up to three working days.
The incident at Quest Laboratories happened last Wednesday and was discovered two days later when clinics began contacting the lab to ask about the test results for these patients.
The spokesman said no other sample batches were affected.
One of the lapses involved an in-house courier who did not follow standard operating procedure when handing over the untested samples to the lab. This resulted in the batch being disposed of alongside old samples. The spokesman added that all the samples were disposed of according to Covid-19 safety requirements.
As at Sunday, the 87 affected clinics have been informed of the incident and 102 patients have been re-tested. Their results have turned up negative, said the lab.
The Health Ministry, which was notified of the incident last Friday, said it is working with the lab and the clinics to contact the affected patients to arrange for them to be reswabbed as soon as possible.
The lab said the retested samples will be prioritised to ensure that affected patients receive their test results without further delay.
The Straits Times was alerted to the matter by a patient who took a swab test last Wednesday at a Toa Payoh clinic after suffering from a runny nose and fever.
When she did not receive her results two days later, her husband called the clinic and learnt that the delay was due to an incident at Quest Laboratories.
The woman, who declined to be identified, said the delay had inconvenienced both her husband and daughter who had to stay home from work and school, respectively, while waiting for the results.
The ministry said it takes a serious view of the incident and is investigating the matter. It added that it will work with the lab to put in place measures so such lapses do not happen again.
"We will take appropriate actions against the laboratory if investigations reveal any breach of the regulations. We will also remind the other licensed laboratories on the need to ensure proper staff training and adherence to their standard operating procedures," added the ministry.
Investigations by Quest Laboratories found two compliance lapses in its standard operating procedures (SOP) involving the handling and disposal of specimens.
The lab said: "The first lapse relates to the handover of specimens from the courier to the specimen reception staff. This occurred at the same time the laboratory staff were disposing of old specimens.
"As a second lapse of SOP, laboratory staff were disposing of specimens in the specimen reception area, leading to the erroneous disposal of the untested batch."
The lab spokesman said relevant employees have been notified of the specific issues that led to the incident and the repercussions. The in-house courier will also receive disciplinary action.
The lab said it has carried out a review of the incident and has implemented corrective and preventive measures.
Quest Laboratories' chief executive Ginny Foo said compliance with procedures relating to the chain of custody is taken very seriously and that this is the first time such an incident has happened at the lab.
"Nevertheless, any such lapse is unacceptable. We have made revisions to tighten our chain of custody, and retraining of staff on the new SOP has already begun," she said.
New measures implemented include colour-coding containers meant for sample delivery to ensure they are easily distinguished from containers meant for disposal.
This will remove the chance of confusion between incoming untested sample batches and batches that have already been tested and have to be disposed of.
The lab has also added a second verification step, requiring all samples for disposal to be verified and signed off by two individuals.
Said Ms Foo: "We deeply regret this failure of our systems and the inconvenience this has caused to the patients, the doctors, and clinic staff involved."