Arduino Master SPI MISO Receive Data

Question

I'm trying to interface an Arduino Mega with an AD7714 ADC. This ADC requires a command to be sent to the communications register (in my case 0x5C) in order to begin a read from the data register.

My question is how do I receive the data that is transmitted from the Slave ADC to the Master Arduino on the MISO line?

At the moment I have this code in an interrupt that is activated when the DRDY goes low:

byte dataIn;
byte dataOut = 0; 
adc_write_reg(0x5C); //tell ADC to read data from data register
dataIn = SPI.transfer(dataOut); //transmit data in order to recieve data??

Thanks!