Insulin resistance can be calculated from two separate tests - current blood sugar and current insulin levels.
The calculation is the HOMA-R which you can look up online.
https://en.m.wikipedia.org/wiki/Homeostatic_model_assessment
Unfortunately, the current insulin test (usually taken first thing in the morning) is not available on the NHS. In fact it appears that most NHS staff do not even know the test exists.
I have paid privately for fasting insulin (not v expensive) and was able to do my own HOMA-R calc.
Your nurse probably doesn’t know this is possible.
The limitation of the calculation is that blood glucose and insulin resistance both vary significantly during the day (in those with dysfunctional bg control) so all you ever get is a ‘snapshot’, but it can still be very useful and informative.
There is often a general assumption on this forum that T2=insulin resistant.
This isn’t always the case, but it is true for the majority.