Calprotectin is a soluble protein that is found in white cells; it is part of the bodies defence mechanism and has strong antibacterial and antifungal properties through its ability to sequester metal ions (calcium, zinc, magnesium).
There is a much calprotectin in white cells as there is haemoglobin in red cells accounting for around 60% of the soluble protein content. In conditions which provoke an inflammatory response the level of calprotectin in the blood can increase significantly and although it is a non-specific marker, it can be used to diagnose and determine the severity of certain conditions in conjunction with the other clinical evidence. The diagnostic advantage of calprotectin detection over other disease markers is that it is stored in the cell and released immediately in response to local inflammation. In contrast, other markers may be generated by downstream pathways or need to be synthesised de novo leading to delays or other factors influencing response.
Examples of conditions where serum calprotectin levels could be useful are:
- Rheumatoid and Juvenile idiopathic arthritis
- Early marker for Sepsis
- Early marker for acute coronary syndromes
- Cystic fibrosis