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P257 Monitoring of calprotectin levels in IBD patients with point-of-care test CalproSmart™

L. Ulanova*1, E. Moerk1

1Calpro AS, Lysaker, Norway

Background

Monitoring of mucosal inflammation makes a pivotal contribution to the therapy of irritable bowel disease (IBD). This requires frequent endoscopic procedures, which are tedious and carry high burden for patients and health services. Therefore, there is a need for an improved non-invasive monitoring method based on a reliable IBD marker, such as calprotectin (CP). Activation of the intestinal immune system during IBD leads to recruitment of neutrophils. CP comprises 60% of cytosol proteins in these cells, thus the amount of CP is proportional to the number of neutrophils and eventually to the degree of the gut inflammation.

Methods

The correlation between routine CalproLab ELISA-based laboratory test for CP and the new point-of-care test (CalproSmart™) was evaluated. The latter consists of a faeces extraction device prefilled with a buffer, a rapid lateral flow test, a support frame and a smartphone application. The study was performed by trained personnel on both fresh and frozen/thawed stool samples from 50 IBD patients during a 2 weeks period. Upon completion of the study, the operator was asked to fill out a survey evaluating design and user experience with the new test.

Results

93% of the CP values measured by the new CalproSmart™ and the routine ELISA test were in good agreement with each other. The deviation between the measurements was less than 15% for the majority of the samples (67% of the total) and less than 25% for the rest of them. The average sensitivity and specificity of CalproSmart™ was calculated as 93% and 78%, respectively; the average positive and negative predictive values were 87% and 88%, respectively. CP values measured by CalproSmart™ and the routine method were scrutinised for fitting into the correct diagnostic window. This demonstrated that the results of the tests coincide in 100% of the cases when it comes to measuring samples from acute patients (CP level above 500 mg/kg); therefore, there were no false negative results. CalproSmart™ and the routine method placed patients with moderate CP levels into the same category in 73% of the cases and healthy individuals—in 86% of the cases. No ‘bleeding through’ between the acute and healthy patients category was observed.

Conclusion

CalproSmart™ demonstrated reliability, high degree of accuracy and correlation with the routine test. It received a positive feedback on its design and user experience—in principle, the test can be used even by patients with no previous experience in using smartphone applications. The new test is economically beneficial, it costs about 10- to 30-fold less than the enormous cumulative price of a single day in at a hospital. The test helps to improve compliance, reduce periods of pain and amount of drugs needed due to monitoring of CP.