Evaluation of 24-h urine containers for urine copper measurement by inductively coupled plasma mass spectrometry.

OBJECTIVE: To determine the necessity for acid-washed containers for 24-h urine copper analysis. METHODS: Copper solutions, with concentrations relevant to clinical decision limits, were prepared by spiking both assay diluent and unknown urine samples with the copper calibrator. Samples were split between plain and acid-washed 24-h urine containers, and copper analysis was performed using inductively coupled mass spectrometry (ICP-MS). RESULTS: Measurement of copper in both spiked diluent and spiked urine samples showed minimal concentration bias between acid-washed and plain 24-h urine containers. CONCLUSIONS: Acid-washed containers are not required for the measurement of copper in 24-h urine samples.