pic - Reducing current consumption in deep sleep mode

This is in relation to the question I asked about deep sleep mode. I'm using PIC18F and it says in the datasheet that in deep sleep it would consume only few nA. But when I configured for deep sleep mode with port set as input, it shows 50uA, which is far more consuming than the limit in data sheet.

It says (under Core Features, page 3):

Power Management with nanoWatt XLP

• Deep Sleep mode: CPU off, Peripherals off, Currents Down to 13 nA and 850 nA with RTCC
  
  
  
  • Able to wake-up on external triggers, programmable WDT or RTCC alarm
  
  
  • Ultra Low-Power Wake-up (ULPWU)
  
  
  
  
  


• Sleep mode: CPU off, Peripherals off, SRAM on, Fast Wake-up, Currents Down to 105 nA Typical


• Idle: CPU off, Peripherals on, Currents Down to 2.3 μA Typical


• Run: CPU on, Peripherals on, Currents Down to 6.2 μA Typical


• Timer1 Oscillator w/RTCC: 1 μA, 32 kHz Typical


• Watchdog Timer: 0.8 μA, 2V Typical

Why is it consuming much more current than specified in datasheet?

And what all things should I be careful of when using deep sleep mode? I have found one similar question.

I would like to have input from those who have played with deep sleep mode in detail. The controller is PIC18F46J53.