6, Rue Ibn Ennafis - Z.I. Lac 3 Tunisie
Tél. : 71 182 500 - Fax : 71 182 250
www.biomaghreb.com
CLINICAL SIGNIFICANCE
Magnesium is a trace element essential for the regulation of energy metabolism, the transmission
of nerve impulses and muscle contractions; it also regulates mood, sleep, behaviour and stress. The
determination of magnesium makes it possible to evaluate several pathological states. Hypermagne-
semia may reflect uremia, diabetic acidosis, dehydration, or Addison’s disease. Low magnesium
levels are seen in patients with malabsorption syndrome, acute pancreatitis, hypoparathyroidism,
glomerulonephritis, or aldosteronism.
PRINCIPLE
In an alkaline medium, calmagite (a metallochromic indicator) forms a colored complex with magne-
sium.
The presence of EGTA makes the reaction specific by limiting interference with calcium. The intensity
of the coloration produced is proportional to the magnesium concentration.
REAGENT COMPOSITION
Reagent 1
Amino-Methyl propanol Buffer
EGTA
1 mmol/l
0,20 mmol/l
Reagent 2 Calmagite 0,30 mmol/l
Reagent 3 Standard magnesium
2 mg/dl
20 mg/l
0,824 mmol/l
SAFETY CAUTIONS
Biomaghreb reagents are intended for use by qualified personnel for in vitro use (do not pipette by
mouth).
- Consult the current MSDS available on request or on www.biomaghreb.com.
- Check the integrity of the reagents before use.
- Disposal of waste: comply with the legislation in force.
For safety reasons, treat any specimen or reagent of biological origin as potentially infectious. Ob-
serve the applicable legislation.
REAGENT PREPARATION
Working Solution :
Mix 1 volume of reagent R1 with 1 volume of reagent R2.
SAMPLE COLLECTION AND HANDLING
Serum or heparinized plasma.
Urine diluted 1/10 with distilled water, acidified to pH: 3.4 with diluted HCI.
PRESERVATION AND STABILITY
- Before opening: Until the expiry date indicated on the label of the box.
- After opening (Working Solution) :
24 hours at 20 -25°C;
4 days at 2-8°C.
ADDITIONAL EQUIPMENT
• Basic equipment of the medical analysis laboratory ;
• Spectrophotometer or Clinical Biochemistry Analyzer.
LIMITS
Use only single use plastic material.
QUALITY CONTROL
External quality control program.
It is recommended to control in the following cases:
• At least one test per series.
• Change of reagent bottle.
• After maintenance work on the analyzer.
If a control value is outside the confidence limits, repeat the procedure using the same control.
Use normal and pathological control sera.
CALIBRATION
The standard of the kit (Reagent 3) or any calibrator connected to a method or reference material.
The frequency of calibration depends on analyzer performance and reagent storage conditions.
Recalibration is recommended in the following cases:
1. changing the reagent lot ;
2. after maintenance work on the analyzer; and
3. the control values are outside the confidence limits.
LINEARITY
The method is linear up to 50 mg/l (5 mg/dl - 2.06 mmol/l).
Above this limit, dilute the sample with 9 g/L NaCl solution and repeat the determination taking the
dilution into account in the calculation of the result. The linearity limit depends on the volume ratio
sample/reagent.
PROCEDURE
Wavelength: 520 nm (500-550) ;
Temperature : 20 -25°C ;
Tank: 1 cm thick
Adjust the spectrophotometer zero on the reagent blank.
Blank Standard Sample
Standard
Sample
Working Solution
-
-
1ml
10 µl
-
1ml
-
10 µl
1ml
Mix and incubate 5 minutes at room temperature.
Read optical densities. Staining is stable for 1 hour.
CALCULATION
Magnesium =
DO. Sample
DO Standard
x
n n = standard Value
n = 2 mg/dl;
n = 20 mg/l;
n = 0,824 mmol/I.
Urine: multiply the result by the dilution factor.
REFERENCE VALUES
Serum, Plasma
1.6 - 2.5 mg/dl
16 - 25 mg/l
0.65 - 1.03 mmol/l
Urine 0.65 – 12.5 mmol/24h
REFERENCES
Gindier E. Clin. Chem. 17, 662, (1971).
MAGNESIUM
Colorimetric Method
Reagent for the quantitative determination
of magnesium in human plasma and urine
FT En 04 Date de MAJ : Janvier 2020 Version B
IN VITRO DIAGNOSTIC USE
