Guidance

NHS Test and Trace: how we test your samples

Updated 26 February 2021

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An overview of the largest diagnostic network in British history, including what happens after you have submitted your sample and how the laboratories process your test.

The national laboratory network

Since the start of the pandemic, we have vastly expanded the nation’s testing capacity by establishing the largest network of diagnostic testing facilities in British history, including the public and private sector, NHS Trusts, PHE labs, and not-for-profit organisations.

COVID-19 swab samples are sent to our laboratories from across the country for analysis. We receive samples from the NHS on the front line and other testing sites, such as COVID-19 drive-through testing centres.

Our laboratories are currently processing around 2 million tests a week and we are using new facilities and technology to process results even faster.

The importance of the national laboratory network

We have built a vast national lab system from scratch at incredible speed over the past year. We have set up an entirely new nationwide network of testing sites to make sure everyone who needs a test can get one.

1 in 3 people in England have received a coronavirus test at least once since the launch of NHS Test and Trace on 28 May. Testing remains a vital part of our response to COVID-19 as we start to cautiously ease lockdown.

The national lockdowns, asymptomatic and symptomatic testing programmes and vaccine roll-out will all have an impact on future testing requirements.

In addition, we have invested in new innovative testing technology which means we can operate faster and respond to surges in demand.

We have also increased staff levels and used robotics to process more tests and improve turnaround times.

During spring 2021 we are consolidating our laboratory network to meet current and forecasted need. Overall capacity will not reduce.

This will give best value for money so that we use our resources as effectively as possible in the fight against COVID-19 and will ensure that the UK has a resilient, long-term, PCR testing capacity that serves the whole nation.

Types of laboratory: the different arrangements

There are different types of laboratories processing COVID-19 swabs.

At the same time as expanding NHS and PHE capacity as quickly as possible – which forms pillar 1 of the testing programme – the government has set up a growing network of Lighthouse labs, partner labs and testing sites (pillar 2) in partnership with a variety of suppliers, including NHS trusts, commercial suppliers, academia and not-for-profit organisations.

This has enabled the processing of test samples from an entirely new network of testing sites across the UK and from new routes such as home testing and mobile units.

This network of laboratories is additional to the rapid expansion of NHS/PHE laboratories. It was set up to ramp up UK testing capacity as quickly as possible in the face of the global pandemic.

Lighthouse laboratories

A Lighthouse laboratory is a high throughput facility that is dedicated to COVID-19 testing for the National Testing Programme.

The Lighthouse laboratories were set up by experienced scientific executives and technical leaders with decades of experience. The rapid and sustained growth and independent quality assessments is evidence of this.

Each Lighthouse laboratory has been reviewed by experts, and each has a clinical virology adviser.

The Lighthouse laboratories are managed through the Department of Health and Social Care (DHSC), NHS trusts, commercial suppliers, academia and not-for-profit organisations.

Partner laboratories

A partner laboratory provides a high volume of testing for the national testing programme alongside its usual activities.

These laboratories are different to Lighthouse laboratories. The laboratories can be acquired through partnership agreements with the public, private and academic sectors and can help to grow capacity by tens of thousands of tests.

The journey of a swab: what happens to your swab

Testing plays a vital role in our effort to fight and contain coronavirus; helping to mitigate the spread of the disease and preventing further transmission.

With hundreds of thousands of swabs processed in our laboratories every day, the experience of taking a coronavirus test at home or at a test site is now familiar to many people in the UK, but the next steps in the process are far less visible.

Here is a summary of what happens ‘behind the scenes’ after your sample enters one of our laboratories for testing. Please note that the processes will vary slightly between laboratories.

  1. Samples arrive at the lab double-bagged and in sealed plastic containers. Each one has its own unique barcode.

  2. A lab operator in protective clothing removes the sample from its bags, inside a biosafety cabinet. These cabinets have negative air pressure such that no aerosol particles can escape into the room and harm the lab operators.

  3. The operator makes sure the sample is viable: that there is enough liquid in the tube and the barcode is in the right place.

  4. Next, the liquid is removed from the sample tube and mixed with a chemical that kills any live virus so it can be handled safely. The sample is then prepared for ribonucleic acid (RNA) extraction, where any genetic material found in the sample is removed.

  5. The samples are added to a machine that uses magnets to extract and wash the RNA. The purified RNA is then placed on ice inside an insulated container to keep it stable.

  6. Plates of purified RNA are removed from the ice and mixed with a number of chemicals called ‘reagents’. These are placed into a polymerase chain reaction (PCR) machine.

  7. PCR testing works by cycling the RNA samples through a variety of different temperatures, a number of times. Each cycle triggers a chain reaction that causes the genes (if present) to replicate and release a detection chemical which tells us if coronavirus RNA is present in a sample.

  8. Once the PCR reaction has been run, the results are carefully checked before being released and uploaded to the lab’s Laboratory Information Management System (LIMS), and then sent on to the National Pathology Exchange (NPEx).This is where the result from the lab is matched to the sample barcode (originally scanned) and subject record.

  9. All results are sent to the NHS Business Services Authority (BSA) who send email and SMS results to the person who took the test. For results relating to England, NPEx matches them to an NHS number and GP record if possible. NPEx also sends all the data to NHS Digital, who split out which results need to go to England, Scotland, Wales and Northern Ireland for public health responses, who then share the information with local authorities.

Locations of the laboratories

We have Lighthouse laboratories and partner laboratories operating with a range of partners across the UK. A new very high throughput laboratory in Royal Leamington Spa will be going online in Spring 2021 which will be run by DHSC.

There are also laboratories in Newcastle, Brant’s Bridge and Plymouth coming online over the coming months which will be operated by NHS trusts in partnership with DHSC.

Automation and technology

As well as announcing new laboratories that are joining the network, we are investing in new technology to process results faster, we are automating parts of the process and we are installing new machines in the laboratories.

Lighthouse laboratories and partner labs continue to maximise capacity through mobilising additional equipment and optimising workflows. For example, we have mobilised new liquid handling robots.

The people behind your swab

A skilled workforce from across the scientific community, with the relevant expertise and experience needed to carry out COVID-19 testing, is working tirelessly to process the samples received. We are extremely thankful for their support and dedication at this time of national need.

The expansion of the laboratory network has resulted in a number of exciting new roles, from junior positions utilising a broad skill base, through to senior positions requiring experienced specialists or those able to oversee entire laboratories.

We will continue to run a rolling recruitment campaign to support the laboratories network and build new jobs and careers in science and the diagnostics industry.

Further information

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