NHS blood tests disrupted as heatwave and net-zero cooling limits force cancellations

The NHS has been forced to cancel blood tests during the summer heatwaves amid net-zero restrictions on air-conditioning units.

Parts of the country are experiencing the fourth heatwave of the year, and record temperatures have caused equipment in some GP practices to become unusable.

Blood samples are also more likely to degrade in the heat, with doctors warned about the risk of false-positive or false-negative results.

However, as part of climate resilience efforts, those responsible for NHS buildings are encouraged to use natural ventilation instead of air conditioning to keep temperatures down.

It means some surgeries struggle to keep room temperatures below the 25C required to store blood samples and test tubes safely.

This summer has already broken temperature records with highs of 35.1C in May and 38C in June, as drought conditions were declared across half of England on Wednesday.

Blood test tubes discarded

NHS sources suggest a number of GP surgeries and pathology providers have been affected by the record-breaking temperatures. Some have been forced to cancel appointments because blood test tubes need to be discarded if they have been subjected to extreme heat for too long.

In some cases, patients have been asked to repeat blood tests, because their samples have degraded.

The NHS Net Zero Building Standard, published in 2023, states that “mechanical cooling should be minimised as far as possible to meet thermal comfort criteria, as well as reduce energy demands”.

Many GP surgeries are based in 20th-century concrete buildings and are unable to retrofit air-conditioning units, either because they are incompatible, funding is not provided, or they would not meet carbon-reduction goals.

Guidance says they should explore every other avenue to reduce temperatures first, such as improving insulation and windows.

New guidance for neighbourhood health centres says air conditioning “should only be introduced where the risk of overheating cannot be adequately mitigated through passive measures alone and where they are clinically required to support safe care delivery”.

Last year, The Telegraph revealed that the NHS had spent at least £1.4bn of taxpayers’ money on net-zero schemes without reducing its carbon footprint.

Dr Munro Stewart, the vice-president of the Royal College of GPs, said many GP practices “weren’t designed to cope” with extreme weather.

He said: “Reliable diagnostics rely on clinical samples being stored in the right conditions and tested in a timely manner.

“GPs and our teams will do our best to ensure samples, such as blood tests, are kept cool – guidelines suggest under 25 degrees – through use of fridges and air-conditioned rooms, but this will be more challenging for some surgeries than others.”

Blood sampling equipment affected

Official guidance is for blood samples to be kept at room temperature, between 15C and 25C, and ideally tested by a lab within 24 hours. They can be put in a fridge overnight if needed.

Blood test tubes need to be discarded if they have been subjected to excessive heat, because it can affect the vacuum seals and any additives, such as preservatives, mixed with the blood.

Broseley Medical Practice in Telford said it had had to cancel all tests for a week during the June heatwave, because of damage to test tubes. It said that “our blood sampling equipment has unfortunately been affected”.

A GP at one rural practice said it had had to “destroy all our blood bottles” because of the heat.

Many blood clinics have been forced to close or cut hours during extreme temperatures, with patients redirected to other facilities, typically those better equipped to cope.

Tyrells Health Centre in Benfleet, Essex, has temporarily closed its phlebotomy clinic because of “operational difficulties with the building”, forcing patients to travel to another site.

An update said: “Work needs to be done to remedy the temperature of the building before it can be used effectively as a venue for a phlebotomy clinic.”

Newmark Park’s drive-through blood clinic, run by Cambridge University Hospitals, has changed its opening hours to 8am to 3pm for the rest of summer.

GPs have also been warned to beware of false-positive or false-negative blood test results because of the impact the heat can have on samples, including on potassium and phosphate levels.

Results falsely lowered or increased

NHS Berkshire and Surrey Pathology Services has issued advice to GPs on the “impact of sustained hot weather on blood sciences test results”.

It said: “With the prospect of high temperatures persisting throughout the summer, we would like to remind clinical colleagues of the potential impact of hot weather on blood test results.

“Temperatures above 25C may lead to falsely lowered potassium and falsely elevated phosphate results because the heat can compromise the ability of red cells to maintain normal balance of intracellular electrolytes. Haemoglobin and platelets may also be falsely increased.”

It warned GPs to be mindful of these when requesting and reviewing results.

Providers of at-home testing kits are also urging patients to delay taking and posting tests.

Some NHS services, such as for sexual health, as well as private providers of health tests for genetics, allergies and fertility, for example, require samples to be sent back via Royal Mail postboxes and vans, in which they could be exposed to extreme heat.

The heatwaves have also led hospitals to declare critical incidents, with services, including diagnostics and pathology, affected.

The University Hospitals of North Midlands NHS Trust was forced to cancel blood tests at its Bradwell Hospital and Bentilee Health Centre clinics during the previous heatwave, with patients told to attend a local walk-in clinic instead.

In Portsmouth, The Queen Alexandra Hospital declared a critical incident after extreme heat caused cooling units to fail, which affected clinical services, including diagnostic facilities.

Earlier this month, The Telegraph revealed that surgeons needed to take breaks mid-operation because of the heat in theatres.

Official guidance from the UK Health Security Agency (UKHSA) warns GPs and hospitals to discard diagnostic tests for bacterial infections, such as tetanus, whooping cough, chlamydia and legionnaires’ disease if they have been subjected to heat.

“Heat-inactivated samples may give rise to erroneous results in several assays and should not be sent,” it says, with false negatives and false positives possible, because of the effect on antibodies and proteins in the blood.

The UKHSA has put in place more heat-health alerts this week, with temperatures of 35C expected on Wednesday.

Claire Coutinho, the Shadow Energy Secretary, said: “Air con is the norm in many countries because it makes workers more productive and people more comfortable.

“To effectively ban it in new homes and hospitals because bureaucrats think it uses too much energy is absurd.

“Energy is a fundamentally good thing and we should use it to improve people’s lives. The Conservatives would end the de facto air con ban and make Britain cool again.”

An NHS spokesman said: “NHS guidance does not restrict the use of air conditioning where it’s needed to deliver safe care.

“Where practices do not have the ability to maintain temperatures within the limits required for pathology equipment, NHS staff are doing all they can to limit the impact for patients and ensure any non-urgent blood tests that require rescheduling are done as soon as possible.”