Usher's Ex-Wife to Judge Drug Test Him NOW Before It's Too Late

Usher's ex-wife Tameka Raymond is freaking out that testing the singer for drugs will soon be useless -- because the more time that passes, the more time Usher has to cleanse his system of illicit substances.

In case you haven't been following -- Tameka demanded Usher take a drug test recently because she thinks the singer is popping pills and who-knows-what-else around their kids.

Usher refused on grounds Tameka's demands were "frivolous and unfounded" and only intended to “harass and embarrass” the singer -- but now, Tameka is taking her case back to the judge in the ex-couple's custody war, pleading with the court to force Usher to take the test despite his refusal.

And according to the docs, Tameka wants the court to make it snappy -- claiming, any further delay will allow Usher to "cleanse" any evidence of drugs from his system.

So far, no word back from Usher's reps.