Calibration and normalization methods for a grating-based sensor design are disclosed. The sensor may be constructed in a manner optimized for both label-free and luminescence, e.g. fluorescence, amplification detection in a single device. Such a sensor, based on grating or another periodical structure with appropriate coating, dramatically increases the diversity of applications and allows realizing novel concepts that provide qualitative and quantitative information/data for each location or capture element in the sensor surface. The invention takes advantage of these different modes to carry out a quality control (QC) step and a calibration of each individual location of the sensor. Thus, the assay data can be flagged according to their quality and local density variations, batch variations and variations in the printed deposition of probes or the materials to the surface can be compensated.