Measuring C-reactive protein levels using point of care testing in primary care could reduce antibiotic prescriptions by up to 10.2 million annually, says Jonathan Cooke

Antimicrobial resistance emerged almost as soon as penicillin and tetracyclines reached the clinic during the 1940s.

Today, health services and governments worldwide recognise that tackling antimicrobial resistance means combining stewardship, education, legislation and clinical and technological innovation.

‘Tackling antimicrobial resistance needs stewardship, education and legislation’

The government’s review on antimicrobial resistance, chaired by commercial secretary to the Treasury Jim O’Neill, among other things, supports the use of diagnostic technologies to reduce unnecessary antibiotic prescriptions.

The new Straight to the Point report, by a multidisciplinary panel of healthcare professionals, summarises evidence around measuring C-reactive protein levels using point of care testing (POCT) in primary care.

CRP POCT is an effective and cost effective means to assist clinicians differentiate viral and self-limiting bacterial respiratory tract infections from more serious infections that require antibiotics. The report makes recommendations to help clinicians, policy makers and clinical commissioning groups facilitate implementation and uptake of CRP POCT.

The evidence

Respiratory tract infections are the reason for 60 per cent of all antibiotic prescribing in general practice - this constitutes a significant cost to the NHS.

However, most acute uncomplicated respiratory tract infections are viral or self-limiting bacterial infections, which can be self-managed and for which antibiotics are inappropriate.

Some prescribers worry that denying patients antibiotics without sufficient justification could undermine their clinical relationship and are concerned about missing developing infections. So, antibiotics may be prescribed as a safety net.

CRP blood levels increase rapidly following infection or injury. CRP POCT can add diagnostic precision to clinical assessment of infections while improving patient and doctor satisfaction during the consultation.

Patients with serious bacterial infections usually show high CRP levels but these are rarely high in viral or self-limiting bacterial infections.

This makes CRP POCT a helpful addition to clinical signs, symptoms and patient history when deciding whether to prescribe antibiotics for the infections.

Patients also can also gain satisfaction with a CRP POCT result rather than an antibiotic prescription. The results of CRP POCT can also aid discussions with patients about appropriate clinical management.

‘CRP POCT delivered by a GP or practice nurse increases quality adjusted life years (QALYs) and reduces costs’

A Cochrane review of randomised or cluster randomised trials reported that CRP POCT significantly reduced GP antibiotic prescriptions for acute RTIs. In one of these studies, the use of CRP POCT showed a difference in GP antibiotic prescribing in RTIs of 41 per cent.

The National Clinical Institute for Health and Care Excellence advocates using CRP POCT in patients presenting with symptoms of lower respiratory tract infection in primary care if pneumonia cannot be diagnosed clinically and it is unclear whether antibiotics should be prescribed. NICE suggests:

  • not offering antibiotics routinely if the CRP concentration is less than 20 mg/l;
  • considering a delayed antibiotic prescription (which patients fill if symptoms worsen or do not improve with self-care) when the CRP level is between 20 mg/l and 100 mg/l; or
  • offering antibiotics if the CRP concentration is greater than 100 mg/l.

Guidance from Public Health England also suggests considering CRP POCT during the differential diagnosis of community acquired pneumonia. Draft NICE antimicrobial stewardship guidelines concluded that CRP POCT might assist antimicrobial stewardship.

A cost effective approach

A CRP POCT costs in the region of £4 per test, while an analyser itself may cost in the region of £1,500 to £2,000 to purchase. 

Pricing may be dependent on local funding discussions. However, over a three year horizon and compared with current standard practice, CRP POCT delivered by a GP or practice nurse increases quality adjusted life years (QALYs) and reduces costs. 

‘CRP POCT could reduce antibiotic prescriptions by up to 10.2 million annually’

CRP POCT has been shown to be a cost effective intervention compared with current management of patients presenting to GP clinics with symptoms of RTI.

Additionally, there are also costs associated with antimicrobial resistance or antibiotic adverse events, which are experienced by about one in 10 people. Some of the POC CRP tests use the same devices as other income generating tests, such as lipids (NHS Health Check), HbA1c and urine albumin-to-creatinine ratio.

Based on the above figures CRP POCT could reduce antibiotic prescriptions by up to 10.2 million annually in England at a saving to the NHS of £56m a year.

Recommendations for commissioners

The report makes several recommendations for commissioners, including that CCGs could:

  • use quality premiums for antibiotic prescribing as an opportunity to review respiratory tract infection diagnostic pathways and implement CRP POCT in primary care;
  • explore funding mechanisms that encourage uptake, while avoiding disincentives and addressing economic benefits that do not accrue to the CCG or healthcare professionals’ budget;
  • use data collected (for instance, to meet requirements of the Care Quality Commission) to audit primary care CRP POCT;
  • consider developing locally incentivised enhanced services or patient group directives to increase implementation and use of CRP POCT in primary care;
  • develop policies and structures that allow local pathology services to support CRP POCT in the community, especially around quality control, training and supply; and
  • work with pharmacists, out of hour services and other professionals to assess CRP POCT in other community settings.

The report concurs with NICE, the European Respiratory Society and PHE that CRP POCT, when properly integrated into primary care consultations for respiratory tract infections, facilitates antimicrobial stewardship and can improve patient satisfaction.

CRP POCT illustrates the potential offered by diagnostic technologies in ongoing efforts to tackle AMR.

More information

Jonathan Cooke is visiting professor in the infectious diseases and immunity section, division of infectious diseases at the Department of Medicine, Imperial College London; is honorary professor in the Faculty of Medical and Human Sciences, at the University of Manchester; and former chair of the Antimicrobial Stewardship Group of Advisory Committee on Antimicrobial Resistance and Healthcare Associated Infection