Analog read micro amps

Can the analog input read micro amps between 50 and a 100 ua. I am building a cloud charge monitor and the base setting is 50ua and goes up when a charged cloud passes over. I would like to make LED's light up as the micro amps increase. Using a Uno

Can the analog input read micro amps

No it only reads voltages and only in the 1mV region at that.

You need to use op-amps to get the signal up into the volt level.

The problem is the AREF voltage you are referencing against and the quality of the ADC of the Atmel chip.

If you are referencing against 1.1v ( like I am with a Mini pro) then 1100mv/1024 steps results in just over a 1mv step.

The other issue you may get is "noise".

Resistor is a sensor, that transform current to voltage to be measurable by arduino.
All you need R, 5 - 10 kOhm to get V 0.5 - 1 V by Ohm law V = I x R