Patient Education on Blood, Urine, and Other Lab Tests| Lab Tests Online. Lab Tests Online (LTO) is an award-winning health information web resource designed to help patients & caregivers understand the many lab tests that are a vital part of medical care. Lab and medical professionals develop and review all content, including articles on lab tests, conditions/diseases, screenings & more. The site is produced by AACC, a global scientific and medical professional organization dedicated to clinical laboratory science & its application to healthcare.