What is the difference between a standard isolation transformer and a medical grade isolation transformer?

The label and cost.

Capacitance between windings, leakage current across primary and secondary, insulation resistance between primary and secondary.

There are two types of isolation transformers, that is, two ways in which the primary and secondary circuits can be separated from each other. They are:

Safety shield – Between the primary and secondary coils, a safety shield is placed with insulation on both sides. This ensures that the leakage current remains within prescribed limits. The thick safety shield complies with strict safety standards. In event of a faulty condition, the electrical path goes directly to ground, providing safety.

Double (or reinforced) insulation – Instead of a shield, two or more insulation layers are packed between the primary and secondary sides. Each individual layer must pass the rigorous safety standards. If one layer breaks or fails, the next layer takes over and provides protection. In general, transformers that use insulation have lower leakage current levels when compared to shield type transformers.

https://www.ksinstruments.net/isolation-transformers-for-medical-industry-applications/#Schematic-of-Medical-grade-Isolation-transformer

Personal Safety at the Work Bench
https://www.youtube.com/watch?v=YHMZsiGb9q0&t=1213s

In this video I teardown my benchtop medically rated isolation transformer by REO Inductive Components. (The REO-MED 1000).

I dismantle the unit to add a twin 13A socket and 4mm banana sockets to make the device more user friendly for general use, and demonstrate the correct way to crimp ring terminals.

AC isolation transformers are used as cleaning and purifying devices between the wall and our gear, but do they work?