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NICE has published diagnostics guidance on 5 blood testsi that aim to show whether infections have been caused by bacteria. The guidance states that, although the tests for measuring levels of the biomarker procalcitonin in the blood show promise, further research is needed into their effectiveness before they can be considered for routine adoption by the NHS in England.

Raised levels of procalcitonin in the blood can show a person has an infection caused by bacteria and can therefore be used for guiding decisions about starting and stopping antibiotic treatment in people with suspected bacterial infection presenting to emergency departments.

Procalcitonin levels rise with increasing severity of infection and decrease as the infection resolves. Therefore procalcitonin levels can also be used as a guide for decisions about stopping antibiotic treatment in people with confirmed or highly suspected sepsis in intensive care units.

Infections, such as pneumonia, may be caused by bacteria or viruses. Bacterial infections can be treated with antibiotics, but these are not suitable for viral infections. However, many patients, especially children, are initially treated with broad-spectrum antibiotics without the cause of the infection being known. Common side effects of antibiotics include mild stomach upset and diarrhoea. Less commonly, people may have an allergic reaction to an antibiotic.

Of most concern is the role of over-use of broad-spectrum antibiotics in the development and spread of antimicrobial resistance, leading to a heightened risk in the future that we may not be able to treat infections effectively. Being able to quickly and accurately find out whether an infection is due to a bacteria or some other agent is therefore important to reduce unnecessary use of antibiotics.

It is also important for clinicians to be able to monitor the progression of sepsis and the response to antibiotic treatment so that antibiotic treatment can be stopped as soon as possible.

Professor Carole Longson, NICE Health Technology Evaluation Centre Director, said: “Tests that can speed up the identification of bacterial infection and also help monitor the progression of sepsis and the response to antibiotic treatment could potentially have a significant positive impact. This could be in terms of resource use – for example by reducing the number of people with suspected bacterial infection admitted to hospital or reducing the length of any hospital or intensive unit stay –  as well as in terms of better patient outcomes – for example by ensuring antibiotics are used appropriately. 

“The Committee concluded that the use of procalcitonin testing with standard clinical practice is unlikely to result in worse clinical outcomes compared with standard clinical practice alone.

“However, there is uncertainty as to whether the results seen in studies showing a decrease in resource use could be replicated in current standard UK clinical practice. For example, the Committee felt that in intensive care unit settings they could not be certain whether the reductions in resource use were the result of using procalcitonin tests or simply because their use involves the use of a clinical protocol to guide care. Because these are standard clinical practice in the NHS, it is uncertain whether the potential reduction in resource in intensive care settings would be realised from the introduction of procalcitonin testing into protocol-guided care.

“Similarly, the Committee heard from clinical experts that for patients with suspected bacterial infection at low risk of sepsis, clinical assessment can be variable, and therefore the clinical benefits of adding procalcitonin to standard clinical practice are uncertain.

“The guidance highlights that research in ‘real-life’ NHS clinical environments would significantly improve our understanding of how best to use these potentially important tests and determine the scale of their impact.”

The diagnostics guidance on procalcitonin tests is available on the NICE website.

For more information call the NICE press office on 0300 323 0142/pressoffice@nice.org.uk or out of hours on 07775 583 813.

Notes to Editors

References

• The 5 tests considered in this assessment are: the BRAHMS PCT Sensitive Kryptor assay (Thermo Fisher Scientific), the VIDAS BRAHMS PCT assay (bioMerieux), the ADVIA Centaur BRAHMS PCT assay (Siemens Healthcare Diagnostics), the Elecsys BRAHMS PCT assay (Roche Diagnostics), and the LIAISON BRAHMS PCT assay (DiaSorin). 

About sepsis

1. Sepsis is a common and potentially life-threatening condition triggered by an infection.
2. Sepsis is diagnosed where there is evidence of systemic inflammation, in addition to a documented or presumed infection. Systemic illness often occurs when bacteria invade normally sterile parts the body. One example of this is the invasion of bacteria or fungi into the bloodstream (bloodstream infection), a process which often causes an inflammatory immune response.
3. Bacterial infections are the most common cause of sepsis and bloodstream infection; however they can also be caused by fungal infections, and less commonly by viral infections.
4. The most common sites of infection leading to sepsis are the lungs, urinary tract, abdomen and pelvis. Other sources of infection leading to sepsis include skin infections (such as cellulitis), post-surgical infections and infections of the nervous system (such as meningitis or encephalitis).
5. Sepsis is a particular problem among patients being treated in intensive care units and severe sepsis is one of the most common reasons for admission to an intensive care unit. It has a mortality rate of 40% to 60%, which increases by about 8% for every hour of delay in starting appropriate antibiotic treatment. Therefore broad-spectrum, high-potency antibiotics are widely used in this setting. Clinicians must be able to rapidly distinguish between different agents of infection, in order to guide appropriate therapy.

About the NICE Diagnostics Assessment Programme 

1. For further information about the NICE diagnostics assessment programme see Developing NICE diagnostic technologies guidance  
2. Topics to be considered by the Programme are routed through the related Medical Technologies Evaluation Programme. Further information about this can be found at Developing NICE medical technologies guidance

About NICE

The National Institute for Health and Care Excellence (NICE) is the independent body responsible for driving improvement and excellence in the health and social care system. We develop guidance, standards and information on high-quality health and social care. We also advise on ways to promote healthy living and prevent ill health.

Our aim is to help practitioners deliver the best possible care and give people the most effective treatments, which are based on the most up-to-date evidence and provide value for money, in order to reduce inequalities and variation.

Our products and resources are produced for the NHS, local authorities, care providers, charities, and anyone who has a responsibility for commissioning or providing healthcare, public health or social care services.

To find out more about what we do, visit our website:www.nice.org.uk and follow us on Twitter: @NICEComms.