In order to determine whether a population is receiving enough iodine in their food, it's necessary to measure this micronutrient in urine samples. The analysis is very difficult because the concentrations are so low--between 10 and 500 parts per billion.
The Centers for Disease Control has certified our lab for analysis of urinary iodide. Certification by the EQUIP (Ensuring the Quality of Urinary Iodide Procedures) program requires three sucessive quarters of successful assays of unknown samples that are provided by CDC, including replicate measurements and interoperator precision. Kudos to Nick Myers, who has been the lead analyst for this challenging task.