A Digital Separation (DS) chip for separating, digitizing and analyzing a fluid sample is presented. The DS chip includes a fluidic layer that prepares and compartmentalizes the fluid sample for analysis. Cliff structures that are adjacent to wells skim the fluid sample and prevent particles, which may interfere with fluid sample analysis, from entering the wells. Skimmed fluid sample analysis occurs in the wells and endpoint data can be collected and used to determine an original concentration of a desired component in the fluid sample very quickly. Using the described apparatus and methods, a fluid sample can be prepared, digitized, compartmentalized, assayed and the endpoint data collected in ˜30 minutes. The apparatus and methods can easily be adapted to provide parallel processing of a sample.