NI-DAQmx has both "raw" and "unscaled" analog reads.
Unscaled reads return data in the native format of the device, read directly from the device or buffer without any scaling. In .NET, you can find unscaled read methods on the AnalogUnscaledReader class.
Raw reads return data in both the native format and organization of the device, read directly from the device or buffer without either scaling or reordering. In .NET, the raw read methods are located on the DaqStream class.
You can find out more information in the NI-DAQmx .NET Framework 1.1. Help or the NI-DAQmx Help, all of which can be accessed from the Start Menu under All Programs >> National Instruments >> NI-DAQ.
-- Chris