Is there a way to test this without a doctor’s blood test, like a glucose meter?
Testing insulin levels
not currently but you can go to any of the 3rd party testing sites and order a blood test w/out involving your doctor. last I checked Life Extension was charging about $40 for this. a doctor on their staff sends you the prescription and they send the results directly to you.
There are some places you can order one yourself from if you are in a large enough city. You just have to search for walk in labs.
currently on sale for $24 and change actually. check to make sure they have supported lab facilities near you before you order.
There is an inverse relationship between ketones and insulin. If ketones are high, insulin is low and the converse is true too.
If you are in the USA, walkinlab.com offer reasonably priced lab tests without needing to go to a doctor. They use labcorp & quest testing labs, The current cost for insulin fasting blood test is $25.