Additional Information:

UFHPL Epic order code: LAB103

CPT Code(s):


Specimen Requirements:

Type: Serum or plasma

Container/Tube: Serum gel or heparinized plasma

Sample Volume: Submit full tubes.

Minimum Volume: 0.5 mL serum or plasma


  • Send specimens in their original tubes.
  • Centrifuge tubes if there is a delay in transport of more than 1 hour.

Storage: Samples are stable for up to 7 days at 2 – 8ºC.

Unacceptable Conditions: Samples with moderate or marked hemolysis will be rejected.

Specimen Retention Time: 5 days


Decreased serum magnesium levels have been observed in cases of diabetes, alcoholism, diuresis, hyperthyroidism, hypoparathyroidism, malabsorption, hyperalimentation, myocardial infarction, congestive heart failure and liver cirrhosis. Increased serum magnesium levels have been found in cases of renal failure, dehydration, severe diabetic acidosis and Addison’s Disease.


This magnesium procedure utilizes a direct method in which magnesium forms a colored complex with xylidyl blue in a strongly basic solution, where calcium interference is eliminated by glycoletherdiamine-N,N,N”,N”-tetraacetic acid (GEDTA). The color produced is measured bichromatically at 520/800 nm and is proportional to the magnesium concentration. (Package Insert, OSR General Chemistry, BAOSR6x89.02, 2012-01)


Within 24 hours

Reference Values:

1.9-2.7 mg/dL