Scottish Trace Element & Micronutrient Reference Laboratory

Scotland's specialised laboratory for trace elements and vitamins in health and disease

Magnesium (Mg)

24 hour urine magnesium is useful in the investigation of unexplained hypomagnesaemia. A low urine magnesium concentration is appropriate for hypomagnesaemia and may suggest inadequate intake or losses from the gastrointestinal system. Urine magnesium results in or above the reference interval may indicate inappropriate urinary loss of magnesium in the face of hypomagnesaemia.

Please note only 24 hour urine samples are analysed at Glasgow Royal Infirmary. Magnesium/creatinine ratio on random urine samples is carried out at the Clinical Biochemistry department at the Queen Elizabeth University Hospital. Random urine samples received at GRI will be forwarded to QEUH for analysis.


Sample Requirements and Reference Ranges for Magnesium

Sample Type

  Urine (24 hour collection)


  Urine: 24 hour urine container.


  Please mix 24 hour urine well before taking an aliquot.

Minimum volume

  1 mL

Reference ranges

  2-11 mmol/24h

Turnaround time

  See this page for STEMDRL TAT targets


  Inductively coupled plasma mass spectrometry


Traceable to reference material produced in accordance with EN ISO 17511:2003 “In vitro diagnostic medical devices. Measurement of quantities in biological samples. Metrological traceability of values assigned to calibrators and control materials” and reference materials with values determined by reference laboratories.

Intermediate Precision (CV)

  See this page for latest data

Measurement Uncertainty, U

  See this page for latest data

Analytical Goals (CV)

  See this page for latest data

EQA Scheme

  UK NEQAS, Birmingham (once per month).

Included in UKAS scope?



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