Diagnostic test waiting times

Background

Diagnostic tests or procedures are a critical part of the care of many patients. Shorter waiting times reduce delays for patients, and can be beneficial if they help people get quicker access to the treatments they need, and reduce uncertainty for patients who may not need treatment.

The six-week diagnostic wait was initially introduced as a ‘milestone’ in March 2008 to support the achievement of the 18-week referral to treatment (RTT) target. Diagnostic waiting times are now part of the NHS Constitution, which pledges that patients should wait less than 6 weeks for a diagnostic test from the time that the request has been sent.

NHS England published new guidance in May 2021 for the prioritisation of waiting lists for diagnostic procedures. It states that waiting lists should be reviewed and prioritised according to clinical need rather than waiting time in areas where more than half of patients have been waiting for more than six weeks. In February 2022, NHS England proposed in the elective recovery plan that testing capacity would increase to 9 million more diagnostic tests and that 160 community diagnostic centres would be rolled out by 2025. As of March 2024, 155 centres opened in England deliver more than 7 million diagnostic tests, which put the government on track to meet its target for the following year. Regarding this achievement as a success would be premature as the expansion of diagnostic centres has to be accompanied by sufficient funding in diagnostic equipment and in the workforce recruitment and retention.

These indicators measure the waiting times of patients still waiting for any of 15 key diagnostic tests or procedures at the end of the month, not including testing for Covid-19. See ‘About this data’ for the full list of tests included.

Waiting list for diagnostic tests

After the introduction of the six-week target in March 2008 the waiting list fell to a low of just over 400,000 patients by December 2008. Over time both the waiting list and the number of tests performed increased, with more than one million people waiting for a diagnostic test prior to the Covid-19 pandemic in February 2020. 

At the start of the Covid-19 pandemic, both the waiting list and number of diagnostic tests carried out fell, before continuing to increase. As of January 2026, the number of people waiting has increased to 1.8 million and the number of tests carried out has increased to around 2.5 million, higher than pre-pandemic levels. 

While NHS England proposes to increase diagnostic testing capacity, other changes to enable direct access to more diagnostic tests may increase demand such that waiting lists for tests will continue.

Wait times of six weeks or more for a diagnostic test

The proportion of patients waiting six weeks or more for a diagnostic test fell rapidly between 2006 and 2008. The proportion of people waiting six weeks or more then remained relatively stable up to start of the Covid-19 pandemic, although the target for fewer than 1% of patients to wait six weeks or longer for a diagnostic test has not been met since November 2013. This objective was removed in the 2024/26 priorities and operational planning guidance. 

In March 2020, the percentage of patients who had been waiting six weeks or more for a diagnostic test began to increase dramatically, reaching 58% in May 2020 – the highest level since records began. Performance has since improved but remains considerably worse than before the pandemic. As of January 2026, one in four patients had been waiting six weeks or more for a diagnostic test, equating to 447,068 people.

The median wait for a diagnostic test has also not recovered since the pandemic, although it has been getting shorter: as of January 2026, half of patients waited 2.6 weeks or longer for a test.

Wait times of six weeks or more by diagnostic test type

Of the 15 key diagnostic tests, the graph displayed above presents data from seven diagnostic tests with the largest test volumes (i.e. at least 50,000 tests conducted in January 2026). 

In January 2026, 752,866 non-obstetric ultrasound scans and 784,561 computed tomography or CT scans were conducted; these respectively accounted each for 31% and 30% of the total volume of diagnostic test activity for that period. 420,436 magnetic resonance imaging (or MRI scans) were conducted, representing 17% of total diagnostic test activity. The rest of the tests each accounted for less than 7% of total activity.

Some of the tests that were more common (MRI scans and non-obstetric ultrasound scans) had a lower proportion of patients waiting over 6 weeks compared with the tests that were less common. In January 2026, 21% of people waiting for an ultrasound waited over 6 weeks. CT scans, despite having a similar volume of activity, had a smaller percentage of people waiting over 6 weeks for a test (11.5%). Audiology assessments, gastroscopies and colonoscopies together accounted for only 16% of the volume of activity, but each had between 29% and 45% of people who needed a test waiting over 6 weeks.