Calprotectin ELISA Sensitive marker for differentiation between chronic infl ammatory and functional bowel disease Fast test performance in 75 minutes Wide measurement range of 1.9 to 2100 μg/g Technical data Coating Monoclonal anti-calprotectin antibodies Calibration Quantitative, in microgram per gram(g/g), 6 calibrators Sample material Stool samples, 1 : 50 diluted in extraction buffer Reagents Ready for use, with the exception of the wash buffer (10 x) and extraction buffer (5 x); colour-coded solutions Test procedure 30 min / 30 min / 15 min (sample / conjugate / substrate incubation), room temperature, fully automatable. Measurement 450 nm, reference wavelength between 620 nm and 650 nm Test kit format 96 break-off wells; kit includes all reagents Order no. EQ 6831-9601 Clinical signifi cance Calprotectin is a calcium- and zinc-binding protein, which is mainly present in neutrophil granulocytes, monocytes and mac- rophages. With a share of 60 %, it is the most frequent protein in the cytoplasm of neutrophils. It is antimicrobial and immu- nomodulatory. In the case of infl ammation of the gastrointestinal tract, leucocytes, among them neutrophils, migrate into the bowel mucosa and release calprotectin, which is excreted with the stool (faecal calprotectin, FC). The concentration of FC is directly proportional to the intensity of the neutrophil infi ltrate in the bowel mucosa. Therefore, faecal calprotectin is a sensitive, accurate marker for intestinal infl ammation. Increased FC level have been found in (active) chronic infl ammatory bowel diseases (CIBD), infections (HIV; bacterial or viral gastroenteritis), colorectal carcinoma, untreated coeliac disease and diverticulitis. Signifi cantly increased values of FC were also observed after treatment with non-steroid antiphlogistics. In the fi rst six months of life, the FC levels in healthy individuals are also increased (depending on the study, between 174 and 550 μg / g) and then normalise until the fourth year of life. The upper limit of the normal range is 50 μg / g. Diagnostic application The determination of faecal calprotectin plays an important role in the differentiation of CIBD and irritable bowel syndrome. The concentration of FC in stool correlates with CIBD activity. Clinical studies investigating the use of FC as a marker for CIBD in irritable bowel syndrome showed a sensitivity between 95 % and 83 % in adults at a specifi city between 91 % and 84 %. In children, a high sensitivity (98 %) at a lower specifi city (68 %) was determined. Faecal calprotectin is suited to predict a relapse in patients in a drug-induced remission stage. The higher the FC values in a CIBD patient, the higher is the risk of a relapse. Permanent remission is associated with low FC concentrations. After resection of affected bowel segments of patients with Crohn’s disease, the FC levels only drop signifi cantly in uncomplicated courses. Determination of FC can help to predict a post-operative recurrence in Crohn’s disease with a high sensitivity. A decrease in the infl ammation of the intestinal mucosa (mucosal healing) correlates with the normalisation of the FC values in CIBD. However, also contradictive results have been described with respect to this. FC determination should not be applied for colorectal carcinoma screening. Autoimmune diagnosticsInfection diagnostics Allergy diagnostics Antigen detection Molecular genetic diagnostics Automation EUROIMMUN AG · Seekamp 31 · 23560 Lübeck (Germany) · Tel +49 451/58 55-0 · Fax 58 55-591 · [email protected] · www.euroimmun.com Detection limit The lower detection limit is defi ned as the mean value of an analyte-free sample plus three times the standard deviation and is the smallest clearly detectable calprotectin concentration. The lower detection limit of the Calprotectin ELISA is 1.9 g/g. Linearity The linearity of the test was investigated by diluting 3 stool samples (214, 568, 1548 μg/g calprotectin) with sample buffer in a lin- ear 1 : 2500 dilution series in 10 % steps. The mean concordance with respect to the expected value was 110 % (96 to 126 %), with a mean correlation coeffi cient of R2 = 0.99. Level scheme Due to the high negative predictive value, measurement of the concentration of faecal calprotectin is especially suited Faecal calprotectin for exclusion of possible chronic-infl ammatory bowel disease if an irritable bowel syndrome is present. The marker can help to substantiate a suspected diagnosis and thus to more promptly choose the best subsequent diagnostic procedure < 50 μg/g 50 – 120 μg/g > 120 μg/g (e.g. endoscopy). Irritable bowel CIBD Borderline result syndrome probable probable Subsequent Subsequent im- measurement aging diagnostic after 2 – 3 weeks methods Sensitivity and specifi city 47 clinically precharacterised patient samples (origin: Europe Clinical evaluation and USA) were analysed with the EUROIMMUN Calprotectin n = 47 positive negative ELISA. The sensitivity was 94.1 %, with a specifi city of 95.5 %. Borderline results were not included in the calculation. positive 16 1 Calprotectin ELISA borderline 53 EUROIMMUN negative 121 Literature 1. Alibrahim B, et al. Fecal calprotectin use in infl ammatory bowel disease and beyond: A mini-review. Can J Gastroenterol Hepatol 29:157-163 (2015). 2. Herrera OR, et al. Calprotectin: Clinical Applications in Pediatrics. J Pediatr Pharmacol Ther 21:308-321 (2016). 3. Smith LA, Gaya DR. Utility of faecal calprotectin analysis in adult infl ammatory bowel disease. World J Gastroenterol 18: 6782-6789 (2012). 4. Lehmann FS, et al. The role and utility of faecal markers in infl ammatory bowel disease. Therap Adv Gastroenterol 8:23-36 (2015). 5. Walsham NE, Sherwood RA. Fecal calprotectin in infl ammatory bowel disease. Clin Exp Gastroenterol 9:21-29 (2016). 6. Peura S, et al. Normal values for calprotectin in stool samples of infants from the population-based longitudinal born into life study. Scand J Clin Lab Invest 78(1-2):120-124 (2018). 7. Galgut BJ, et al. The Value of Fecal Markers in Predicting Relapse in Infl ammatory Bowel Diseases. Front Pediatr 5:292 (2018). 8. Li F, et al. Fecal calprotectin concentrations in healthy children aged 1-18 months. PLoS One 10(3):e0119574 (2015). 9. Boon GJ, et al. Are faecal markers good indicators of mucosal healing in infl ammatory bowel disease? World J Gastroenterol 21: 11469-11480 (2015). 10. Wright EK, et al. Measurement of fecal calprotectin improves monitoring and detection of recurrence of Crohn’s disease after surgery. Gastroenterol 148(5):938-947.e1 (2015). 11. Lee SH, et al. Fecal calprotectin predicts complete mucosal healing and better correlates with the ulcerative colitis endoscopic index of severity than with the Mayo endoscopic subscore in patients with ulcerative colitis. BMC Gastroenterol 17(1):110 (2017). 12. Patel A, et al. Fecal Calprotectin Levels Predict Histological Healing in Ulcerative Colitis. Infl amm Bowel Dis 23(9):1600-1604 (2017). 13. A, et al. The intra-individual variability of faecal calprotectin: a prospective study in patients with active ulcerative colitis. J Crohns Colitis 9(1):26-32 (2015). Autoimmune diagnosticsInfection diagnostics Allergy diagnostics Antigen detection Molecular genetic diagnostics Automation EUROIMMUN AG · Seekamp 31 · 23560 Lübeck (Germany) · Tel +49 451/58 55-0 · Fax 58 55-591 · [email protected] · www.euroimmun.com EQ_6831_D_UK_A02, 04/2019.