Described herein are methods and devices for capturing and determining the identity of molecules using nanopores. The molecules can be counted, sorted and/or binned rapidly in a parallel manner using a large number of nanopores (e.g., 132,000 nanopores reading 180 million molecules in 1 hour). This fast capture and reading of a molecule can be used to capture probe molecules or other molecules that have been generated to represent an original, hard to detect molecule or portions of an original molecule. Precise counting of sample molecules or surrogates for sample molecules can occur. The methods and devices described herein can, among other things, replace flow cytometers and other counting instruments (e.g., while providing increased precision and throughput relative to a flow cytometer). In some cases, the devices and methods capture and hold particular molecules or surrogates of molecules in the nanopores and then eject them into clean solution to perform a capture, sorting, and binning function similar to flow cytometers.