A urine specimen for urinalysis should be collected in a clean, dry, disposable container. If the sample is to be cultured, the container must be sterile. The preferred method is the "midstream clean-catch" collection. The external genitalia are cleansed with a sterile cleansing towelette or equivalent. The first part of the urine stream is discarded while collecting only the midstream portion of the urine.
More details on the standards for urine collection can be found in the CLSI guide GP16-A3: Urinalysis; Approved Guideline - Third Edition.