Serum procalcitonin differentiates inflammatory bowel disease and self-limited colitis.
BACKGROUND
The distinction between idiopathic inflammatory bowel disease (IBD) and infectious, usually self-limited enterocolitis is still a diagnostic dilemma. Procalcitonin (PCT) is the prohormone of calcitonin and is considered a specific marker of bacterial infection. The aim of this prospective study was to determine the value of PCT in differentiating flares of IBD from self-limited colitis. In addition, because standard laboratory inflammatory parameters are poorly correlated with disease activity in IBD, the relation between PCT levels and disease activity was investigated.


METHODS
A total of 76 patients (26 Crohn's disease, CD; 25 ulcerative colitis, UC; and 25 patients with self-limited enterocolitis) were enrolled. Serum levels of PCT were measured by a sandwich immunoluminometric assay. C-reactive protein (CRP) levels, white blood cell counts, and stool cultures were obtained from all patients. Disease activity was assessed by the Crohn's disease activity index (CDAI) and the Truelove index for CD and UC, respectively.


RESULTS
Patients with self-limited enterocolitis showed significantly higher PCT levels when compared with IBD patients (0.36 ng/mL, range 0.18-1.7 vs 0.10 ng/mL, range 0.08 0.5, p < 0.001). For a PCT value of > or =0.4, the sensitivity for self-limited colitis was 92% and specifity 96%. The positive predictive value (PPV) for self-limited colitis was 96%, whereas the negative predictive value (NPV) was 93%. In IBD patients, PCT levels were in the normal range although significantly higher in active disease when compared with inactive disease (0.13 ng/mL, range 0.08-0.5 vs 0.09 ng/mL, range 0.08-0.15, p < 0.001). This difference was less pronounced for CD (0.11 ng/mL, range 0.08-0.2 vs 0.09 ng/mL, range 0.08-0.15, p < 0.05) than for UC (0.14 ng/mL, range 0.08-0.5 vs 0.09 ng/mL, range 0.08-0.11, p < 0.01). In CD, PCT levels correlated significantly 0.5, p < 0.01). with the CDAI (r =0.05, p <0.01).


CONCLUSIONS
The measurement of PCT offers two diagnostic options in IBD. Supranormal levels indicate self-limited enterocolitis. Furthermore, although within the normal range in IBD, PCT levels may serve as a new serological marker of disease activity.
Department of Internal Medicine I, Robert Bosch Hospital, Stuttgart, Germany. klaus.herrlinger@rbk.de
Klaus R
KR
Herrlinger
Rike
R
Dittmann
Gunther
G
Weitz
Jan
J
Wehkamp
Diether
D
Ludwig
Matthias
M
Schwab
Eduard F
EF
Stange
Klaus
K
Fellermann
D001424:Bacterial Infections / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D003093:Colitis, Ulcerative / Q000097:blood; D003424:Crohn Disease / Q000097:blood; D003937:Diagnosis, Differential; D004760:Enterocolitis / Q000097:blood*; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood*; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity
D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide