Transparency data

Management information on lateral flow device (LFD) test registration rates: 22 July 2021

Published 22 July 2021

Applies to England

Supplementary information on LFD test registration rates to support information presented at the Public Accounts Committee meeting on 8 July 2021.

Background

This publication presents management information on NHS Test and Trace to estimate the proportion of LFD tests dispatched which have been registered. It also includes information from an internal survey on the number of people who register their test result. This has been published to support information presented at the Public Accounts Committee meeting on 8 July 2021.

LFD usage has been subject to both scrutiny and speculation since first deployed in the UK. While there is no definitive data source to accurately measure usage across the population, available data on tests dispatched from warehouses and test results registered by users has been used to estimate usage. This approach was included in the National Audit Office report on NHS Test and Trace published on 25 June 2021.

There are several limitations with using the data available on LFD tests dispatched and tests registered to estimate LFD usage:

• it does not acknowledge the possibility that tests are taken and not recorded

• it does not account for tests which have been dispatched but are not with individuals and available for use

• it does not account for the government policy in some sectors where the initial emphasis was on testing as opposed to reporting the results

This analysis estimates the LFD registration rate by adjusting the dispatch and registration volumes to account for the above limitations. This applies stock management policy and government testing policy to model expected use and compare to the volume of registered tests.

Also included in this report are the results from an internal behavioural tracking survey to understand the proportion of people who register their test result after taking an LFD test. This information was also referred to in the Public Accounts Committee meeting on 8 July and details can be found below.

Regular data on NHS Test and Trace is published weekly on GOV.UK

Estimated proportion of LFD tests dispatched which have been registered

To estimate the proportion of LFD tests dispatched which have been registered, any LFD tests which were not with individuals and available for use, or which were not expected to be registered, are excluded from the dispatch volumes. The following exclusions have been applied to the total number of LFD tests dispatched, for the purposes of calculating the proportion of LFD tests dispatched which have been registered:

1. LFD tests dispatched to adult social care and the NHS prior to 15 January 2021 – when LFDs were initially deployed in England the focus was to protect care homes and hospitals by ensuring they had sufficient supplies and appropriate training for use. This meant that during early deployment the drive and technology to enable result registrations was not as strong. Excluding tests dispatched to these sectors prior to 15 January 2021 ensures dispatches are aligned with result registration performance.

2. LFD tests in wholesale warehouses – LFD tests dispatched include test volumes which NHS Test and Trace has dispatched from their warehouses. At this point some are sent to wholesalers for onward distribution. Tests with wholesalers are therefore excluded as they are not with individuals for use.

3. LFD tests within settings – LFD tests dispatched include tests which have been dispatched to various settings such as schools and care homes but have not yet been distributed to individuals. Therefore, these are excluded.

4. LFD tests with individuals pending use – individuals are typically issued with a set of 7 tests and government policy encourages all users to test twice a week, therefore each set equates to 3 and a half weeks’ supply. This analysis therefore assumes that a proportion of the prior month’s tests dispatched will not yet be used and are excluded.

The number of tests excluded are rounded to the nearest 1,000 as they are estimates based on the assumptions listed above with associated uncertainty. This uncertainty should be taken into account when interpreting the figures. For further information on the exclusion reasons and the assumptions see the methodology section.

Table 1: total number of LFD tests dispatched that have been excluded from the analysis, up to and including 26 May 2021, England

Exclusion reason	Number of LFD tests
LFD tests issued to NHS staff prior to 15 January 2021	52,468,000
LFD tests issued to adult social care settings prior to 15 January 2021	23,391,000
LFD tests in wholesale warehouses	10,910,000
LFD tests within settings awaiting onward distribution to individuals	106,977,000
LFD tests with individuals pending use	61,994,000
Total number of LFD tests excluded	255,740,000

Table 2: estimated number of LFD tests dispatched and available for use, up to and including 26 May 2021, England

Breakdown of total LFD tests dispatched	Number of LFD tests
Total LFD tests dispatched	690,761,924
LFD tests excluded	255,740,000
Estimated total number of LFD tests dispatched available for use	435,021,924

In order to estimate the proportion of LFD tests dispatched which have been registered, the total number of LFD tests conducted and registered must be adjusted to align with the methodology for estimating dispatch volumes in tables 1 and 2. The number of tests conducted and registered in adult social care and the NHS prior to 15 January 2021 are therefore excluded from the total as seen in tables 3 and 4. Without this adjustment the registration rate would be artificially inflated. The numbers of tests excluded are rounded to the nearest 1,000 tests as they are estimates based on assumptions with associated uncertainty. This uncertainty should be taken into account when interpreting these figures.

Table 3: LFD tests conducted and registered that have been excluded from the analysis, data up to and including 26 May 2021, England

Exclusion reason	Number of LFD tests conducted and registered
NHS LFD tests prior to 15 January 2021	4,189,000
Adult social care LFD tests prior to 15 January 2021	931,000
Total number of LFD tests excluded	5,120,000

Table 4: adjusted number of LFD tests conducted and registered for the purposes of estimating registration rates, data up to and including 26 May 2021, England

Breakdown of LFD tests conducted and registered	Number of LFD tests conducted and registered
Total number of LFD tests conducted and registered	96,402,549
LFD tests excluded	5,120,000
Adjusted total number of LFD tests conducted and registered	91,282,549

Having adjusted both the number of LFD tests dispatched and the number of LFD tests conducted and registered, the estimated LFD test registration rate is 21%. Without adjusting for the tests which were not available for individual use and those which were not expected to be registered, this figure is 14% as stated in the NAO report.

This data is also available in tables 1 and 2 of the accompanying spreadsheet.

Estimated proportion of people that do not register their LFD test

An LFD test produces a result on the device almost immediately, without it being automatically recorded. Therefore, some results might not be captured. In settings where self-reporting LFD testing procedures are in place, such as schools, NHS and the general public ordering home test kits, it is likely that the number of tests conducted are underreported. However, it is the individual’s statutory duty to register each test result. The proportion of people that use an LFD test but do not register the results, given in the Public Accounts Committee meeting on 8 July 2021, was approximated using survey responses.

The Department of Health and Social Care (DHSC) carries out fortnightly UK-wide polling to track public worry, concern, awareness of risks and preventative measures being taken in relation to the coronavirus. These surveys are used internally to inform communications on coronavirus aiming to increase adoption of recommended health behaviours and to inform policy decision-making.

Fieldwork for the most recent survey was conducted between 28 and 30 June 2021. 329 English respondents (19% of the total English sample) said they took a coronavirus test in the last 7 days and that their most recent test was an LFD test. These respondents were asked where they reported the result of their test, selecting from a list of options. Multiple selections were permitted.

Of these, 63% said they reported the result of their most recent test on GOV.UK or by phone with NHS Test and Trace. This means that 37% of these respondents did not say they reported their result on GOV.UK or by phone with NHS Test and Trace.

The survey is representative of the English population but relies on self-reported data which may not wholly reflect actual behaviour.

Table 5: how respondents who took a lateral flow device test in the last 7 days reported their test result, 28 to 30 June 2021, England^{[footnote 1]}

Base: respondents who took a coronavirus test in the last 7 days and the last test they took was an LFD test (329, unweighted)	Percentage of respondents
I registered my result on GOV.UK	51%
I registered my result by phone with NHS Test and Trace	16%
I informed my employer	16%
I informed the school, nursery or further education college where I or a member of my family study	7%
I informed the university where I or a member of my family study	6%
I informed friends or family I had recently met before taking the test	6%
I informed friends or family I was planning to meet after taking the test	10%
Other	0%
I did not report the result to anyone	17%
Summary: I registered my result on GOV.UK or I registered my result by phone with NHS Test and Trace	63%
Summary: Did not select I registered my result on GOV.UK or I registered my result by phone with NHS Test and Trace	37%
Summary: Reported result	83%

This data is also available in table 3 of the accompanying spreadsheet.

In addition, surveys are also carried out by NHS Test and Trace as part of the programme evaluation. Recently a survey into asymptomatic testing was carried out between 30 April and 10 June 2021. The results of this survey are due to be published by NHS Test and Trace in summer 2021.

Methodology

Data sources

The figures in this publication are management information collected by NHS Test and Trace with modelling assumptions applied to estimate figures where necessary.

The survey figures in this publication are from an internal DHSC behavioural insights survey.

LFD tests dispatched

The number of LFD tests dispatched counts the number of individual LFD tests which NHS Test and Trace have dispatched from warehouses between 29 September 2020 and 26 May 2021. Tests are counted by the date requested for dispatch and are counted individually, regardless of the LFD test pack size. Orders which are on hold or cancelled and stock which is distributed between warehouses are not included. The number of tests dispatched are reported for England only which is defined based on the location the item was dispatched to. LFD tests dispatched to locations outside of England are therefore not included. The number of tests dispatched has been published previously at management information on NHS Test and Trace: 24 June 2021.

LFD tests available for use

To estimate the LFD test registration rate, the number of LFD tests dispatched should be adjusted to exclude any LFD tests which are not available for use and therefore cannot be registered. The following information outlines the rationale and assumptions made when excluding certain test volumes.

LFD tests dispatched prior to 15 January 2021 for use in adult social care and the NHS

When LFDs were initially deployed in England the focus was to protect care homes and hospitals by ensuring they had sufficient supplies of LFD tests and appropriate training for use. This meant that during early deployment the drive and technology to enable result registrations was not as strong. For the purpose of this analysis the volume of dispatched tests to adult social care and the NHS for all of November and December 2020 and half of January 2021 have been removed. This assumes an equal distribution of tests dispatched across the month of January. This is to align result registration performance to the period it was both required and recorded systematically. Tests dispatched to adult social care includes care homes, adult day centre care, hospices, extra care housing, domiciliary care and supported living. Tests dispatched to NHS includes primary care organisations, NHS trusts and the independent sector for use by staff and non-staff.

LFD tests in wholesale warehouses

LFD tests dispatched include test volumes which NHS Test and Trace has dispatched from their warehouses. At this point some tests are sent to wholesalers for onward distribution. This analysis uses management information received direct from the wholesalers regarding their working stock that has yet to be distributed for onward use. The number of tests with wholesalers as of 25 May 2021 are excluded from the total number of tests dispatched, to acknowledge that these tests are not available for use.

LFD tests within settings awaiting onward distribution to individuals

LFD stock replenishment cycles and policies mean that in settings where LFD testing has been rolled out, such as schools and care homes, they typically hold between 4 and 6 weeks of LFD working stock. Therefore, when measuring LFD tests registered as a proportion of tests dispatched it would under-report use. For the purposes of estimating LFD registration rates it has therefore been assumed that stock issued to these settings each month would not be handed to end users for use until 6 weeks later. The number of LFD tests dispatched to these settings in May and late April are therefore excluded from the total number of LFD tests dispatched as these tests are not expected to be available for use. This adjustment only affects tests dispatched to these settings and does not include tests via the home channel or universal offer.

LFD tests with individuals pending use

When individuals receive tests they are typically issued with a box of 7 tests for their personal use. Government policy encourages all users to test twice a week, therefore each box equates to 3 and a half week’s supply. For the purpose of this analysis it is assumed that the user will work through their tests throughout the month upon receipt. LFD tests are issued weekly across various settings, therefore individuals will receive and start to use their testing supply at different times. This analysis therefore assumes that a proportion of the prior month’s dispatch will not yet be used. With testing spread across a 4-week period this assumes a growing proportion of total tests dispatched will remain.

Adjusted total number of LFD tests conducted and registered

The total number of LFD tests conducted counts all of the LFD tests which have been used and the test result was registered. It does not count tests where the individual did not register their result. Tests are counted by the date the test was taken.

In order to estimate the proportion of LFD tests dispatched which have been registered, the total number of LFD tests conducted and registered must be adjusted to align with the methodology for adjusting the dispatch volumes available for use. The number of tests conducted and registered in adult social care and the NHS prior to 15 January 2021 are therefore excluded from the total number of tests conducted and registered. Without this adjustment the registration rate would be artificially inflated.

The methodology for determining the total number of LFD tests conducted and registered by NHS staff is slightly different to the figures reported in the weekly Test and Trace statistics. This is because it includes tests taken by non-staff in addition to staff.

The methodology for determining the total number of LFD tests conducted and registered in adult social care is different to the number of LFD tests conducted in care homes as reported in the weekly Test and Trace statistics. This is because these figures include all elements of adult social care such as care homes, adult day centre care, hospices, extra care housing, domiciliary care and supported living.

Proportion of people that do not register their LFD test

Fieldwork for the survey was conducted between 28 and 30 June 2021. 329 English respondents (19% of the total English sample) said they took a coronavirus test in the last 7 days and that their most recent test was an LFD test. These respondents were asked where they reported the result of their test, selecting from a list of options. Multiple selections were permitted.

All fieldwork was completed online and invitations to participate were sent to members of online panels, drawing a random sample based on profiled key socio-demographic data. To improve representativeness, interlocking age and gender quotas and regional quotas were set for responses, proportional to population statistics for the UK.

A total sample of approximately 2,000 UK respondents is used per wave, with approximately 1,700 English respondents per wave. Results have been weighted according to age, sex and government office region to reflect the profile of UK adults.

While the sample is representative of the UK population, the data is self-reported so may not completely reflect actual behaviour.

Strengths and limitations

Estimated proportion of LFD tests dispatched which have been registered

Strengths

While there is no definitive data source to accurately measure LFD test usage across the population, available data on tests dispatched from warehouses and test results registered by users has been used to estimate usage. This approach was included in the NAO report on NHS Test and Trace published on 25 June 2021. There are several limitations with using the data available on LFD tests dispatched and tests registered in this way, which centres on the assumption that all tests dispatched are with end users and are available for use. The figures in this report therefore allow for a more accurate estimation of the registration rate for LFD tests. It takes into account the following:

• LFD tests dispatched to settings where there was not the drive or the digital infrastructure available to report test results

• LFD tests which are not yet with individuals and available for use

• LFD tests with individuals but unlikely to be used due to the testing frequency set out in government policy

Limitations

In order to estimate the proportion of LFD tests dispatched which have been registered several assumptions have been made. These assumptions are associated with the following limitations:

• half of all LFD tests dispatched to adult social care settings and the NHS in January 2021 are excluded as these settings were not provided with the guidance or technology to report their test results until 15 January 2021. By excluding 50% of the dispatch volumes for January, this assumes there was an equal distribution of tests dispatched across the month of January which may not be the case

• similarly, half of all LFD tests registered to adult social care settings and the NHS in January are excluded to align with the exclusion of the tests dispatched. By excluding 50% of the registered tests this assumes an equal distribution of tests were registered across the month of January which may not be the case

• LFD tests dispatched in May to specific settings are excluded as institutions such as schools and colleges keep a stock level of around 4 to 6 weeks. This however assumes that all tests dispatched in May are being dispatched for the purposes of stock replenishment. However, this may not be the case as settings are able to distribute tests at their own discretion

• an increasing proportion of LFD tests dispatched throughout April to individuals are excluded to account for tests that are with individuals but have not yet been used by 26 May. This is limited in that it assumes complete compliance with the twice-weekly testing policy, whereas in reality individuals may test more or less frequently

1. Survey question asked: “How, if at all, did you report the result of your test?” ↩