This topic serves as web content restoration, because due Forum engine update (February 2021) it was lost a relative message / post.
Here there is my BM869 this tested at high resistance measurements by the use of measuring standards.
Best measuring practice for such high resistances, we need to use short in length test leads with banana ends, so us to plug at then alligator clips.
At measuring such high resistances, we do not touch with our hands neither the test leads and also neither the meter it self.
Bench top multimeter or dedicated resistance meters these has a third connection named as GUARD, this is similar to earth connection and stabilizes the measurement reading.
At measuring such high resistances the DMM will use a tiny portion of DC current, and not all handheld DMM are capable to measure tiny portion of DC current with major success.
In order of us to fight measured reading instability we are forced to use FREE HANDS measurement / test leads connection.
Here are my three sample pictures for you to see.