Inflammation occurs when tissues are injured by bacteria, trauma, toxins, heat, or other causes. Both C-Reactive Protein (CRP) and Procalcitonin (PCT) are released into the bloodstream during inflammation, can be used as systemic inflammatory markers.
CRP is one of the acute phase reactive proteins. In inflammation, infection and tissue damage, CRP is mainly produced by the liver under the stimulation of cytokines. Conventional CRP can be used to evaluate infection, tissue damage and inflammatory diseases. High-sensitivity CRP (hs-CRP) can be used as an auxiliary means to identify the risk of cardiovascular disease, in conjunction with the traditional clinical diagnosis methods of coronary syndromes. And it is also useful as an indication of recurrence of acute coronary syndrome or coronary artery disease.
PCT is the precursor peptide of the mature hormone calcitonin, which is released by multiple tissues under the stimulation of infection and inflammation. PCT has a good correlation with infection and sepsis, which is used for the differential diagnosis of bacterial and non-bacterial infections, differential diagnosis of sepsis, guiding the use of antibiotics and testing the effects of treatment, and prompting the prognosis of the disease. When a bacterial infection occurs, the PCT concentration increases and is related to the severity of the disease. After the infection is controlled, the PCT value decreases.
Because CRP and PCT are nonspecific, they can be used to identify a generalized inflammatory state and can aid in the differential diagnosis.