Need to compare 2 depth images (16 bit)...

I want to compare 2 16-bit depth images in a shader (if possible). One of the images would be what the camera sees (its depth image). The other comes from Primesense camera. Would it be possible to create a 16-bit color texture, like RGBA4444, and just go ahead and stuff the 16-bit gray values in, and inside the shader, use the value as a 16-bit value (rather than a 4-component color)?