Validation of Two Calprotectin Rapid Tests in Daily Routine.

BACKGROUND

The differentiation of organic and functional intestinal diseases and monitoring of disease activity in inflammatory bowel diseases are frequent challenges in daily clinical routine. Fecal calprotectin is a noninvasive screening marker for intestinal inflammation. Its quantification by ELISA is considered to be the gold standard, but an increasing number of semiquantitative and quantitative point-of-care-tests (POCT) have been launched to optimize the duration between sample input and result.

METHODS

The objective of this study was to evaluate sensitivity and specificity of two fecal calprotectin rapid test assays compared to an enzyme-linked immunosorbent assay (ELISA) as gold-standard considering the costs, time to result, and effort. For this purpose, fecal samples were collected from 68 patients with either confirmed Crohn´s disease (CD) (n = 37), confirmed ulcerative colitis (UC) (n = 21) or with confirmed IBS (n = 10) and analyzed with all three tests.

RESULTS

Both rapid tests analyzed in this study revealed a high sensitivity in comparison to ELISA defined as gold standard (93.0 % PreventID®, 99.9 % Quantum Blue). The negative predictive value of Quantum Blue was better than of PreventID® (99.8% vs. 84.2%). When analyzing the capacity of all applied tests to differentiate IBD from IBS, the sensitivity of all three tests was similar, but the ELISA was more specific than the POCTs. The expense of the POCT per sample is significantly above the costs per sample for the ELISA.

CONCLUSIONS

Both POCTs, Quantum Blue and PreventID®, provide high diagnostic accuracy and were less time consuming in clinical routine than quantification of fecal calprotectin by ELISA. This makes these tests excellent candidates for the use in clinical routine. The routine application of ELISA techniques for the quantification of fecal calprotectin levels is a valid option in laboratories or clinical departments with high quantities of samples to allow prompt follow up for patient management.