Collect a random urine specimen, no preservatives
Transfer 4mL (minimum 1.0mL) of urine to a Screw cap transfer vial/tube (Mayo T914)
Refrigerated (preferred) – 14 days
Ambient – 72 hours
Frozen – 14 days
Colorimetric endpoint assay
Random Magnesium/Creatinine Ratio: ≥0.035 mg/mg
Reference values have not been established for patients <18 years or >83 years of age