Diagnostic accuracy of fecal calprotectin assay in distinguishing organic causes of chronic diarrhea from irritable bowel syndrome: a prospective study in adults and children.
BACKGROUND
Fecal calprotectin (FC) has been proposed as a marker of inflammatory bowel disease (IBD), but few studies have evaluated its usefulness in patients with chronic diarrhea of various causes. We evaluated the diagnostic accuracy of a FC assay in identifying "organic" causes of chronic diarrhea in consecutive adults and children.


METHODS
We consecutively enrolled 70 adult patients (30 males, 40 females; median age, 35 years) and 50 children (20 males, 30 females; median age, 3.5 years) with chronic diarrhea of unknown origin. All patients underwent a complete work-up to identify the causes of chronic diarrhea. FC was measured by ELISA.


RESULTS
In adult patients, FC showed 64% sensitivity and 80% specificity with 70% positive and 74% negative predictive values for organic causes. False-positive results (8 of 40 cases) were associated with the use of aspirin (3 cases) or nonsteroidal antiinflammatory drugs (1 case) and with the presence of concomitant liver cirrhosis (3 cases). False-negative results mainly included patients suffering from celiac disease (5 cases). Patients with IBD (9 cases) were identified with 100% sensitivity and 95% specificity. In pediatric patients, sensitivity was 70%, specificity was 93%, and positive and negative predictive values were 96% and 56%. False-negative results (11 of 35 cases) were associated mainly with celiac disease (6 cases) or intestinal giardiasis (2 cases).


CONCLUSIONS
FC assay is an accurate marker of IBD in both children and adult patients. In adults, false negatives occur (e.g., in celiac disease) and false-positive results are seen in cirrhosis or users of nonsteroidal antiinflammatory drugs. Diagnostic accuracy is higher in children.
Carroccio
Antonio
A
Internal Medicine, University Hospital, 90124 Palermo, Italy. acarroccio@hotmail.com
Iacono
Giuseppe
G
Cottone
Mario
M
Di Prima
Lidia
L
Cartabellotta
Fabio
F
Cavataio
Francesca
F
Scalici
Calogero
C
Montalto
Giuseppe
G
Di Fede
Gaetana
G
Rini
GiovamBattista
G
Notarbartolo
Alberto
A
Averna
Maurizio R
MR
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003109:Colonic Diseases, Functional / Q000175:diagnosis*; D003937:Diagnosis, Differential; D003967:Diarrhea / Q000175:diagnosis*; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D007223:Infant; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis*; D008297:Male; D008875:Middle Aged
D039841:Leukocyte L1 Antigen Complex