Blood levels of a protein, called c-reactive protein (CRP), could be helpful as an additional biomarker to diagnose pneumonia in patients hospitalized with acute respiratory symptoms, according to a study published in the Journal of Biomarkers. This is important because it can be difficult to diagnose pneumonia based on chest radiographs, which are often unspecific.
In the study, “The Diagnostic Value of Serum C-Reactive Protein for Identifying Pneumonia in Hospitalized Patients with Acute Respiratory Symptoms,” a team of researchers led by Dr. José Porcel of Arnau de Vilanova University Hospital in Lleida, Spain, recorded cases of patients with acute respiratory symptoms who were admitted into the emergency department of the hospital during the winter season of 2013-14.
A total of 1,473 people were admitted and, of these, 923 (62.3%) were included in the study. Of these patients, 557 had a final diagnosis of pneumonia and 366 had another type of lower respiratory tract infection, such as acute bronchitis or acute worsening of chronic obstructive pulmonary disease (COPD).
In addition to chest radiographs, the researchers also measured the levels of CRP in the blood of the patients. They found that those diagnosed with pneumonia had higher blood levels of CRP compared to those with COPD or acute bronchitis.
Specifically, the team identified levels of CRP above 200 mg/L as likely for a pneumonia diagnosis, and levels below 75 mg/L as unlikely. However, they emphasized that further research should be conducted to validate the accuracy of this CRP range.
“The results of our study suggest that the routine use of serum CRP levels in hospitalized patients with acute respiratory symptoms can help clinicians to differentiate pneumonia from other respiratory infections,” the researchers concluded.