. 2021 Jul 29;9(8):956. doi: 10.3390/healthcare9080956

Table 2.

Summary of current findings in terms of fecal calprotectin and COVID-19. CRP: C-reactive proteins; IL-6: interleukin-6; FC: fecal calprotectin.

Authors, Country	Design	Sample Size	Primary Results/Conclusions
Effenberger et al. [31] (August, 2020) Innstruk (Austria)	Cohort	Total, n = 40	Mean Calprotectin Concentrations: patients with diarrhea 80.2 mg/kg vs. patients without diarrhea 17.3 mg/kg.
		Patients with diarrhea, n = 22	Patients with acute diarrhea showed higher FC level if compared to patients without diarrhea. FC concentration correlates with IL-6 but not to other markers of inflammation such as CRP. Viral RNA was not detected in stools from patients with ongoing diarrhea, and no relation was found between SARS-CoV-2 RNA and FC.
		Patients without diarrhea, n = 18
Giuffrè et al. [37] (August, 2020) Trieste, Italy	Cohort	Total, n = 25	Approximately, 84% of patients showed increased FC despite being asymptomatic for gastrointestinal symptoms. Two patients with particularly high FC developed spontaneous intestinal perforation.
Britton et al. [38] (September, 2020) New York (USA)	Retrospective	Total, n = 43	SARS-CoV-2 RNA was seen in stools of 41% of patients, being slightly more prevalent in patients with diarrhea.FC did not correlate withgastrointestinal symptoms or viral level detected.
Ojetti et al. [39] (November, 2020) Rome (Italy)	Cohort	Total, n = 65	Mean Calprotectin Concentrations: patients with radiological interstitial pneumonia had higher FC if compared to patients without anomalies (71.3 vs. 11.9 µg/g, p < 0.001).
Ojetti et al. [39] (November, 2020) Rome (Italy)	Cohort	Total, n = 65	Patients with normal FC were younger (33 vs. 56 years old, p = 0.0024) and mostly men (87% vs. 52.6%). Also, patients with elevated FC were more likely to have gastrointestinal symptoms (47.4% vs 15.2%, p = 0.006).
Zerbato et al. [38] (June, 2021) Trieste, Italy	Cohort	Total, n = 51	The authors did not detect any differences in FC concentrations between patients with and without diarrhea. However, the patients with SARS-CoV-2 RNA detection in fecal samples had higher FC (74 vs. 39 mg/kg, p < 0.001), lower neutrophil counts (5550 vs. 4390 cell/µL, p < 0.035), higher D-Dimer (723 vs. 580 ng/mLFEU).