PRESTIGE 24i LQ MG page 1
Cat. No 4-229
PRESTIGE 24i LQ MG
DIAGNOSTIC KIT
FOR DETERMINATION OF
MAGNESIUM CONCENTRATION
INTRODUCTION
Magnesium in human organism occurs mainly in bone (about 50%) but is
present also intracellularly in other tissues. Magnesium serves as a cofactor
for multiple enzymatic reactions involved in nucleic acids synthesis, transport
and production of energy. Magnesium is important in neuromuscular
conduction and activation. Reduced magnesium level generates: concentration
disturbances, fatigue, muscle tremor, anxiety state.
METHOD PRINCIPLE
Magnesium forms a purple coloured complex in alkaline solution. In the
presence of EGTA, the reaction is specific. The intensity of the purple colour
is proportional to the magnesium concentration.
REAGENTS
Package
Cat. No 4-229
(24-TRAY)
4 x 60 ml
1-Reagent
The reagent is stable up to the kit expiry date printed on the package when
stored at 2-8 C. Stability on board of the analyser at 2-10 C: Prestige 24i –
3 weeks, Biolis 24i Premium – 3 weeks. The reagent is air sensitive, to extend
reagents stability it is recommended to keep reagent’s bottles recapped on the
board of analyser. Protect from light and avoid contamination!
Concentrations in the test
xylidyl blue
0.15 mmol/l
EGTA
0.1 mmol/l
buffer (pH 11.5)
detergent
Warnings and notes
Product for in vitro diagnostic use only.
The reagents contain sodium azide (< 0.1%) as a preservative. Avoid
contact with skin and mucous membranes.
It is recommended to use disposable plastic materials. If it is not
possible, the glassware should be washed with 1% HCl solution and
rinsed with plenty of distilled water.
SPECIMEN
Serum, heparinized plasma free from hemolysis, 24-hours urine.
Recommended anticoagulants: heparine lithium, sodium or ammonium salt.
Serum should be separated from red blood cells as soon as possible after
blood collection, because erythrocytes contain approximately 3 times the
magnesium concentration found in normal serum.
Urine preparation: acidify urine with some drops of concentrated
hydrochloride acid to pH 1.0. Then dilute 1 part of acidified urine with
4 parts
of distilled water. Multiply the result by 5. Mix well samples before analysis.
Serum and plasma can be stored up to 7 days at 2-8ºC. For longer storage
samples should be frozen at -20ºC.
24-hours urine samples can be stored up to 7 days at 2-8ºC.
Nevertheless it is recommended to perform the assay with freshly collected
samples!
PROCEDURE
This reagent may be used in automatic analysers Prestige 24i, Biolis 24i,
Sapphire 400 and Prestige 24i Premium, Biolis 24i Premium, Sapphire 400
Premium.
1-Reagent is ready to use.
Avoid foaming.
1-Reagent put on basic position in reagent tray.
For reagent blank deionized water is recommended.
REFERENCE VALUES
6
serum / plasma
mg/dl
mmol/l
newborn 2 – 4 d
1.5 – 2.2
0.62 – 0.91
children 5 mo – 6 y
1.7 – 2.3
0.70 – 0.95
6 – 12 y
1.7 – 2.1
0.70 – 0.86
12 – 20 y
1.7 – 2.2
0.70 – 0.91
adults
1.6 – 2.6
0.66 – 1.07
24-hours urine:
mg/24h
mmol/24h
72.9 – 145.8
3 – 5
It is recommended for each laboratory to establish its own reference ranges
for local population.
QUALITY CONTROL
For internal quality control it is recommended to use the CORMAY SERUM
HN (Cat. No 5-172) and CORMAY SERUM HP (Cat. No 5-173) for
determination in serum or CORMAY URINE CONTROL LEVEL 1
(Cat. No 5-161) and LEVEL 2 (Cat. No 5-162) for determination in urine with
each batch of samples.
For the calibration of automatic analysers systems the CORMAY
MULTICALIBRATOR LEVEL 1 (Cat. No 5-174; 5-176) and LEVEL 2
(Cat. No 5-175; 5-177) is recommended.
The calibration curve should be prepared every week (Prestige 24i, Biolis 24i
Premium), with change of reagent lot number or as required e.g. quality
control findings outside the specified range.
PERFORMANCE CHARACTERISTICS
These metrological characteristics have been obtained using the automatic
analysers Prestige 24i and Biolis 24i Premium. Results may vary if a different
instrument or a manual procedure is used.
Sensitivity (Prestige 24i):
0.14 mg/dl (0.057 mmol/l).
Sensitivity (Biolis 24i Premium):
0.06 mg/dl (0.025 mmol/l).
Linearity (Prestige 24i):
up to 7.3 mg/dl (2.99 mmol/l).
Linearity (Biolis 24i Premium):
up to 7.6 mg/dl (3.12 mmol/l).
Specificity / Interferences
Haemoglobin up to 0.313 g/dl, ascorbate up to 62 mg/l, bilirubin up to
15 mg/dl, triglycerides up to 1000 mg/dl and calcium up to
20 mg/dl do not interfere with the test.
Precision (Prestige 24i)
Repeatability (run to run)
n = 10
Mean
[mg/dl]
SD
[mg/dl]
CV
[%]
level 1
level 2
2.03
4.24
0.02
0.03
0.75
0.64
Reproducibility (day to day)
n = 10
Mean
[mg/dl]
SD
[mg/dl]
CV
[%]
level 1
level 2
1.94
3.93
0.05
0.10
2.32
2.42
Precision (Biolis 24i Premium)
Repeatability (run to run)
n = 10
Mean
[mg/dl]
SD
[mg/dl]
CV
[%]
level 1
level 2
2.05
4.21
0.02
0.04
1.07
0.93
Reproducibility (day to day)
n = 10
Mean
[mg/dl]
SD
[mg/dl]
CV
[%]
level 1
level 2
1.97
4.16
0.04
0.07
2.12
1.76
Method comparison
A comparison between magnesium values determined at Prestige 24i (y) and
at ADVIA 1650 (x) using 93 samples gave following results:
y = 1.0422 x - 0.1068 mg/dl;
R = 0.970
(R – correlation coefficient)
