Hair follicle drug tests involve removing a small hair sample for laboratory testing. Results can show if a person has been using certain drugs or prescription medications in the previous 3 months. It ...

A polymerase chain reaction (PCR) test detects genetic material from a pathogen or abnormal cell sample. Ways of collecting samples include a nasal swab, a saliva swab, or taking a sample of blood.

Your doctor can order a stool ova and parasites (O&P) test to check for parasites and their eggs in your stool, or feces. It’s a relatively easy and common test. Your doctor will likely ask you to ...