How to check stability/integrity of voltage reference IC?

[Red_Micro]

I'm using TL431 shunt regulator as the voltage reference of 2.5V for an ADC. If I don't add a cap at the output, this introduces non-linearities in the ADC measurements. When I add a 10uF cap, the reference becomes more stable reducing accuracy errors in ADC. My question is how I can measure or see this behavior with let's say an scope? How can I see this instability of the regulator to understand how it changes when sampling?

[bob91343]

You could build two of them and use a differential probe.