Prime Minister Jacinda Ardern has admitted "errors have been made" after Director-General of Health Ashley Bloomfield revealed a COVID-19 test backlog of 32,000.
Dr Bloomfield revealed that the dramatic rise in the number of COVID-19 cases "led to a delay in the processing of around 32,000 samples", nearly 30 percent of which had to be sent to Queensland for processing.
"I want to apologise to people whose tests have been delayed," Dr Bloomfield said during a press conference held at the Ministry of Health in Wellington on Tuesday.
"Our labs are committed to processing all those tests and those people will get a result even though it's been delayed," Dr Bloomfield said.
"We have sent text messages out to those people whose results have been delayed encouraging them if they still have symptoms or are developing symptoms to go and get a test and of those who received the text around 12,000 had gone and got a PCR or most of them a rapid antigen test."
Dr Bloomfield said the results of the tests "may be less sensitive" due to the delay in processing.
"If we had recognised this delay a little earlier, we may have been able to redirect and share capacity around the network, but once the samples are in a lab it's very hard to take them out because they're in the system.
"We've also used other things to help reduce this backlog including sending just over 9000 tests to Queensland over the weekend.
"I do want to emphasise that the delays are not the fault of our labs or the staff there. They have been working incredibly hard throughout the pandemic and have done phenomenal work over the last few weeks."
Dr Bloomfield cited staffing shortages and supply-chain issues as some of the reasons for the delay. He acknowledged that the introduction of rapid antigen tests (RATs) provided "immediate" relief for labs.
The Opposition has long been calling for the Government to adopt wider use of RATs, which until last week were only available to select organisations deemed essential as part of the Omicron response plan.
"Today's admission will be little comfort to the thousands of Kiwis still waiting for results and unable to get back to work or school," National's COVID-19 spokesperson Chris Bishop said on Tuesday.
"But it's hardly a surprise, given the Government failed to order rapid antigen tests until the very end of last year - and even then, they didn't order nearly enough."
Ardern said the Government "worked quickly" to rectify the issue.
"Yes, clearly errors have been made, but at the same time, we have a workforce that has worked incredibly hard over the last few years. Our job is to fix those errors and make sure they don't happen again in the future."
Last week, as the number of daily cases topped 5000, the final phase of the Omicron plan was implemented, with RATs now the dominant form of testing.
Throughout the pandemic the Government has been reluctant to introduce RATs because they are less reliable than the traditional nasal PCR swabs. But there are now too many daily cases for labs to keep up with.
"PCR testing has served us incredibly well for just over two years just as we've sought to find and respond to every case of COVID-19 at the border and in the community," Dr Bloomfield said.
"That included it playing a major role in our Delta outbreak that started last August and that we had very nearly got control of before Omicron appeared.
"But with thousands of new cases each day and nearly 20,000 today, we did reach the point last week where wide use of rapid antigen testing became both useful and appropriate.
"It also became clear that PCR testing capacity was not keeping up with demand."
The high number of cases meant labs were unable to continue pooling, where samples from several people are tested together in one go - a strategy that worked when there was less likelihood of positive test results.
In the Delta outbreak, up to 140,000 tests could be processed per day and surge up to 170,000 for a few days, thanks to pooling. But without pooling it's only around 30,000 a day.
The number of daily cases has not yet reached 30,000, so technically the labs should have been able to keep up. Dr Bloomfield said he's sought an explanation and an external review.
The backlog is 32,000 tests where it's taken five days or more to process. It peaked at around 50,000.
Dr Bloomfield explained how pooling was once effective.
"Typically, samples are pooled with about three to five samples during the early stages of an outbreak to increase the processing throughput, for example during the August 2021 peak of the Delta outbreak, some labs increased pooling to eight to 10 samples per run.
"We continued to use pooling in the early part of this outbreak. However, it becomes less feasible when test positivity rates rise due to the likelihood that there would be at least one if not more positive test in each group of pooling samples.
"Two Thursdays ago, prior to the wider rollout of rapid antigen tests, 17 of the 20 DHBs across the country recorded positivity rates of more than 5 percent. Prior to the 7th of February, so less than a month ago, none of our labs had ever exceeded that 5 percent threshold.
"The swift increase in positive cases right across the country effectively prevented labs from using pooling in the space of just a couple of days."
Dr Bloomfield said the wider availability of RATs will help ease the pressure. Of the nearly 20,000 positive cases announced on Tuesday, only a couple of thousand were confirmed via PCR.
More than 5000 RATs have been distributed across the country in the last seven days, with 12 million in central stores, and 16 million expected to arrive this week.
