Magnesium

4th most abundant cation and 2nd most intracellular cation

Magnesium

_____% in the bone, ___% in the muscle, organs and soft tissue

_____% for serum and RBC (___ bound albumin)

53% bone

46% muscle

>1% serum and RBC

Majority of magnesium is being excreted in the feces, ____% and ___% through the kidneys

60% feces

40% kidneys

Renal threshold of magnesium

0.60-0.85 mmol/L

Regulation of Magnesium

______________ - 25—30% of regulation

______________ - increases renal absorption of Mg and enhances intestinal reabsorption of Mg in the intestine

_____________ - increases renal excretion of Mg

Kidneys

Parathyroid Hormone

Aldosterone

Specimen used for Magnesium (3)

Serum

Plasma (Lithium/Ammonium heparin)

24 hr urine

Urine must be acidified with ______________ to avoid precipitation

Hydrochloric Acid

Magnesium interferences:

_______________ - False increase because Mg+2 is 10x greater inside RBCs

_______________ - These anticoagulants are unacceptable

Hemolysis

EDTA, Citrate, Oxalate

Methods of Measurement

_____________________ - Reddish Violet at 532nm

_____________________ - Colored Complex at 660nm

_____________________ - Mg + Chromogen

_____________________ - Red lake colloidal precipitate

_____________________ - Fluorescence at 380-410 nm

_____________________ - Reference Method

_____________________ - Polyvinyl Chloride membrane

Calmagite

Formazan dye

Methylthymol blue

Titan yellow

Fluorescent method

Atomic Absorption Spectrophotometry

Ion Selective Electrode