Why must you submit a urine sample (bioassay)?

• A. To assess lung function
• B. To measure blood sugar
• C. To detect all possible health parameters
• D. To assign dose from tritium; can detect other radionuclides inside the body

Answer: (D)

Submitting a urine sample for bioassay is about measuring what radioactive material is inside your body, not outside. For tritium, the urine excreted reflects the amount that has entered your body because tritium behaves like hydrogen and distributes with body water. Analyzing that urine allows scientists to estimate the internal radiation dose you’ve received. The test can also reveal other radionuclides if present, giving a broader view of internal contamination. It isn’t a test of lung function or blood sugar, and it isn’t a general health screen; its purpose is to quantify internal radiological burden and assign dose from any radionuclide, starting with tritium.