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Test Code LAB405 Magnesium - Urine

Department

CHEMISTRY

Collection Requirements

Random urine.

Primary Collection Container

Yellow Urine Vacutainer (No Additive)

Transport

Urine refrigerated

Preferred Transport Temperature

Refrigerated

Processing

Adjust pH to less than 3 with 6N HCl.

Aliquot, centrifuge and refrigerate.

Stability

Ambient: 1 week

Refrigerated: 1 week

Minimum Testing Volume

0.1 mL

Reference Range

No reference ranges have been established.

Methodology

The magnesium method is a modification of the methylthymol blue (MTB) complexometric procedure described by Connerty, Lau, and Briggs. MTB forms a blue complex with magnesium. Calcium interference is minimized by forming a complex between calcium and Ba-EGTA (chelating agent). The amount of MG-MTB complex formed is proportional to the magnesium concentration and is measured using a bichromatic (600 and 510 nm) endpoint technique. Siemens Dimension Vista.

Performed

Sunday – Saturday

Reported

As completed

CPT Codes

83735

Unacceptable Conditions

Urine not acidified.