Smoking35 I'm sorry but you are wrong.

A DOT drug test sample requires 45 ml, 30 for the A sample, 15 for the B sample. 2 ounces is 60 mls which allwos them to make both samples 30 ml if they really want to (some collectors will do that if they are given enough).

Almost all drug test will require 45 mls or less. This will take care of most split samples.

The split sample is if you would like to challenge a positive test with a different lab at your cost. They will test the B sample. Good luck though because it is even difficult to actually get them to responde to the request for testing the B sample at your request. It's like they just ignore you.