The 24-hour urine pilot study was conducted March - June 2013 in three NHANES locations. A random half-sample of non-pregnant US adults, aged 20-69 who were examined in the NHANES mobile examination center were selected. Participants received instructions, started and ended the urine collection in a urine study mobile examination center (UMEC), and answered questions about collection. A random half of participants who collected a complete 24-h urine were asked to collect a second 24-h urine. Urinary sodium, potassium, chloride, and creatinine excretion were analyzed.
Participation rates in two other post-examination components, the Physical Activity Monitor and the Dietary Recall, were monitored to determine whether collecting a 24-hour urine had an effect on response rates for the two components.
