Section 11.04.01.562 - URINE SAMPLES01.Phenylbutazone. No urine sample taken from a horse authorized to use phenylbutazone may exceed one hundred sixty-five (165) micrograms total of phenylbutazone or its metabolites per milliliter of urine.02.Lasix. Any horse whose post-race urine creatinine is less than forty (40) milligrams creatinine per one hundred (100) milliliters urine, and the ratio of urine furosemide to urine creatinine does not exceed fifteen hundredths (.15), with urine furosemide being measured in micrograms per milliliter of urine will be said to be positive for Lasix overage.Idaho Admin. Code r. 11.04.01.562