A medical laboratory scientist (MLS) or clinical laboratory scientist (CLS) or medical technologist (MT) performs diagnostic testing of blood and body fluids in clinical laboratories. The scope of a medical laboratory scientist's work begins with the receipt of patient or client specimens and terminates with the delivery of test results to physicians and other healthcare providers. The utility of clinical diagnostic testing relies squarely on the validity of test methodology. To this end, much of the work done by medical laboratory scientists involves ensuring specimen quality, interpreting test results, data-logging, testing control products, performing calibration, maintenance, validation, and troubleshooting of instrumentation as well as performing statistical analyses to verify the accuracy and repeatability of testing. Medical laboratory scientists may also assist healthcare providers with test selection and specimen collection and are responsible for prompt verbal delivery of critical lab results. An estimated 70% of medical decisions are based on laboratory test results.