The bitRead() accepts all variables. It is not even a function but a macro.
It is located in Arduino.h: https://github.com/arduino/ArduinoCore-avr/blob/master/cores/arduino/Arduino.h#L111
#define bitRead(value, bit) (((value) >> (bit)) & 0x01)
The return value is 0 or 1.
The bit number starts counting from 0.
Bit 0 is always shown on the right.
You don't need to test this with I2C. You can make a small sketch with a value and print that value hexadecimal, binary and with bitRead().
If your variable 'something' is zero, then that bit was really zero.
Please show a full sketch. There is a website for that: https://snippets-r-us.com/