Acute respiratory tract infections are one of the most common reasons for adults presenting to primary care settings in the USA. Infectious agents causing diseases such as acute bronchitis, sinusitis and pharyngitis can be difficult to distinguish if they are of viral or bacterial origin. When they are of viral origin, antibiotics are of little or no benefit for reducing risks of serious complications, nor significantly reduce time to symptom resolution. Between 2007 and 2009, approximately 51% of adult patients were prescribed antibiotics unnecessarily for these types of acute respiratory tract infections. Diagnostic and prognostic uncertainties, due to overlapping signs and symptoms between bacterial and viral infections and perceived patient demand for antibiotics, have been identified as drivers of inappropriate antibiotic prescribing. Overuse of antibiotics is associated with the emergence of antibiotic-resistant microorganisms, making treatment more difficult.
What is C-Reactive Protein?
C-reactive protein (CRP) is produced in the liver and is found in blood plasma. It increases in response to inflammation following interleukin-6 secretion by macrophages and T cells. Its physiological role is to bind to lysophosphatidylcholine expressed on the surface of dead or dying cells and some bacteria in order to activate the complement system via the C1Q complex.
C-Reactive Protein Point-of-Care Test
Recently, in an attempt to reduce inappropriate prescribing, C-reactive protein (CRP) point-of-care test (POCT) levels from a finger-prick blood sample underwent clinical assessment in the United States. Within 4 minutes the blood sample could produce CRP POCT levels which were used to differentiate between viral, which usually produces a slight increase in CRP, and bacterial infections, associated with a large increase in CRP. This test is currently used in some European countries but it has yet to be tested in the USA.
The C-reactive protein point-of-care test could be valuable for clinicians when it comes to treatment choices leading to a decrease in unnecessary antibiotics prescriptions and less bacterial resistance. Although his test can clear up some diagnostic uncertainties, some clinicians had concerns regarding the effects of unnecessary testing and potential inaccuracy of CRP POCT. Implementing indications for the use of CRP POCT use may lead to a change in the current guidelines for acute respiratory tract infections.
1. Hardy, V., Thompson, M., Keppel, G. A., Alto, W., Dirac, M. A., Neher, J., . . . Cole, A. (2017). Qualitative study of primary care clinicians’ views on point-of-care testing for C-reactive protein for acute respiratory tract infections in family medicine. BMJ Open, 7(1) doi:http://dx.doi.org/10.1136/bmjopen-2016-012503