RATIONALE: Most people who abuse substances underestimate their consumption in an attempt to conform to social norms or protect themselves. Few accurately describe or overestimate consumption; some may deny it. Therefore, on admission, quantitative and qualitative toxicology screens are done to validate information obtained from the client.NURSING PROCESS STEP: AssessmentCLIENT NEEDS CATEGORY: Psychosocial integrityCLIENT NEEDS SUBCATEGORY: NoneCOGNITIVE LEVEL: Comprehension