[Solved] Some cocaine abusers sense imaginary bugs crawling under their skin,forcing abusers to scratch their skin into open sores. Laboratory Specimen: A sample of tissue, blood, urine, or other material from the body used for analysis and diagnosis in a laboratory. Sputum Specimen: A sample of mucus coughed up from the lungs, collected for laboratory analysis to help diagnose respiratory diseases. Surgical Incision: A cut made through the skin and tissues during surgery to gain access to the area being operated on. Occult Blood: Refers to the presence of blood in the feces that is not visible to the naked eye, usually detected by chemical tests.