How do you advise patients with recurrent nephrolithiasis and polyuria who require more than one 24 hour collection jug and need to adequately mix the specimens prior to aliquoting for mail-off lab analysis?

My understanding of methods for dealing with large volume collections (more than 1 container) is that each container is sampled and tested separately, and the results are combined by the processing laboratory to provide the actual 24-hour totals. While one could envision methods for mixing the conte...

A good question! Urinary composition over the 24-hour cycle varies with dietary intake.

I would advise the patient to request 2 collection containers from the laboratory. The patient collects all urine produced in the first 12 hours, and then fills the return laboratory specimen container 1/2 full. ...

This is not a common problem. I use Litholink (no financial links whatever), and that company can send out two containers and maintain responsibility for combining them. Ideally, one merely adds one to the other. Proportional volume additions are best done within the lab.