||The 2nd morniing urine and collection in sterile urine cup are preferable.
||Keeping at 4°C is preferable but not essential.
||Protease inhibitors may be necessary for proteinuric urine samples, but not for normal urine samples unless exosome analysis is planned.
||Centrifugation is desirable to minimize proteins releasing from insoluble contents (cells and casts).
||Adjustment of urine pH to 8.0 with 1 M Tris buffer (pH 8.0) may help solubilization of aggregates after thawing. Times of freezing and thawing need to be recorded. Samples with identical freeze-thaw history should be used for comparison proteomics