Multimeter reliability and safe use over 3600 meters above sea level ?

[HangarAndino]

Greetings from Bolivia, South America.
I was serching for a good multipurpose multimeter, but all are rated at a top working altitude of 2000 meters, and my beloved city is above 3600 meters.
So my question is how trustworthy and safe would be to use one of those multimeters at this height?
Do you know a multimeter with a higher altitude rating ?
Thanks for the help.

[Someone]

Keysight have their standard altitude specification up to 3,000m and some of their military products are specified to 30,00ft. Beyond that you would derate the voltage rating, and possibly have some loss of accuracy. The data is usually presented in the Paschen curve, and the slope in that region of the graph suggests much less than a factor of 2 derating.

[Lightages]

The main concern is for the safe voltage rating. As already said the maximum voltage should be de-rated. I am in Chile and live at 2500m, not quite as high as you do. I don't think accuracy would be affected much if at all. Here is how you derate, from a document on measurement standards: