An evaluation of calprotectin as serum marker of preeclampsia: a systematic review of observational studies

Calprotectin is calcium-binding protein which can be found in the cytosol of neutrophils. Several studies have studied its levels in preeclamptic women; however, to date there is no consensus regarding its effectiveness in the field. To investigate whether serum calprotectin levels are elevated among preeclamptic women compared to healthy controls. We used Medline (1966-2015), Scopus (2004-2015), ClinicalTrials.gov (2008-2015), Cochrane Central Register of Controlled Trials CENTRAL (1999-2015) and Google Scholar (2004-2015) search engines in our primary search, together with reference lists from included studies. Seven studies were finally included in our systematic review which recruited 439 women (245 with preeclampsia and 194 healthy controls). Their methodological quality was relatively high as they reached a score that ranged between 6 and 7 according to the Ottawa-Newcastle classification. All included studies reported that the serum calprotectin levels were significantly elevated among preeclamptic patients (p < 0.05). One study suggested that patients with severe preeclampsia have significantly higher levels of calprotectin than patients with mild preeclampsia (p = 0.01). However, to date there is no evidence regarding specific cut-off values which would help screen women for preeclampsia, or even follow the course of the disease. Current evidence suggests that serum calprotectin is significantly raised among women with preeclampsia during the third trimester. Future research is needed to reach firm conclusions regarding its use as a potential screening and surveillance marker during the pregnancy course of women at risk of developing preeclampsia.