How long does urine stay fresh if refrigerated it is for a drug and alcohol test?

depends what you mean by fresh. If you mean no bug growth then it also depends on the preservatives. No preservatives, less than 24 hours. with boric acid preservative, maybe a weekend.

If you mean the substances tested in the urine. e.g. glucose, bence Jones protein etc, then it depends on what the test is for.

The fresher the sample, the more accurate the result