Yes 42 is the first number of prediabetes (42-47 incl).
https://www.diabetes.co.uk/diabetes_care/blood-sugar-level-ranges.html
Sadly there are drs that are complacent about raised levels, possibly thinking it’s progressive so why bother until it’s diagnosable. Others that don’t realise it’s included in the range. Others that barely acknowledge prediabetes as a thing and plain old human error in not telling you. Many of us have similar stories, some only coming to light years later after full blow T2 has been identified.
Even these lab tests have some degree of variance that’s considered normal and the same person can get different results from different labs. Also it’s a scale. There’s no magic thing that triggers at a particular number things just go from ideal to less ideal to this is a problem gradually.
You’ve still got good warning. Look at your diet and eliminate excessive carbs (all colours and types brown/wholemeal only makes just a little difference) and sugars, particularly those in processed foods that have little nutritional benefits. Try and eat real foods you can recognise the ingredients as food not chemicals. Limit vegetable and seed oils as much as you can. Replace these useless carbs with more non starchy veg and salad items, more unprocessed proteins and naturally occurring fats. This will likely shift any stuff belly fat which also helps stop things progressing. Basically the same approach as if T2 but likely without the need to be as extreme about it.
