Immunoturbidimetric Assay for the Detection of Microalbumin in Urine
Introduction
Almost half of all insulin
dependent diabetics develop a diabetic nephropathy (DNP),
with protein in the urine and a decline
in the filtration rate, during the course of their
disease. If a DNP remains undetected, it leads to
irreversible kidney failure that necessitates
dialysis treatment, or kidney transplant.
Additionally, high blood pressure, through
atherosclerotic changes in the blood vessels that supply
the kidneys, can lead to inadequate blood supply
and to nephropathy. Microalbuminuria is
defined as a slight increase in urinary albumin
(20 – 200 mg/L), caused by a disturbance in
the glomerular filtration barrier.
Microalbuminuria may have various causes; it may be the
concomitant product of profound physical
stress, fever, cardiac insufficiency, or poor
regulation of hypertension. After the
elimination of the causative factors, the levels can
return to normal. However, a constant, detectable,
prolonged microalbuminuria suggests damage
to the glomerular filter. The progression
of kidney damage can be reduced by means of
metabolic adjustment, blood pressure control
and early pharmaceutical intervention. The
increased risk of cardiovascular disease that
accompanies a nephropathy can, at the same time,
also be reduced.
Test Principle
Many of the methods traditionally
used for the detection of albumin lack the
sensitivity and precision necessary for the
detection of microalbumin. The DCL Microalbumin
assay is a two reagent procedure, utilizing
an immunoturbidimetric method which
provides the sensitivity necessary for the
accurate determination of urinary albumin
(microalbumin) in the test sample. During the
test, when sample is mixed with anti-human albumin
goat antiserum, agglutination is caused
by the antigen-antibody reaction. The
resulting turbidity is measured at 340 nm and 700 nm
where the concentration of microalbumin in
the test sample is quantitatively determined.
Key Features and Benefits
Liquid-Stable Format
–
Liquid stable technology eliminates the need for
reagent reconstitution procedures, saving
time and labor while reducing potential
errors and reagent waste.
Flexibility In Testing
–
Test using fully automated procedures . . . an
extensive listing of instrument applications
is readily available.
Minimal Sample & Reagent Volumes
– Most automated procedures require
less than 10
μL
of sample and less than 300 μL of combined reagent per test.
Reliable Results
– The
assay demonstrates superior performance
characteristics with regard to linearity, accuracy,
precision and sensitivity.
Accommodating Packaging
–
Each compact, operator-oriented test
kit contains enough reagent to perform a
minimum of 250 tests.
Proven Performance
– A
documented history of testing in some of the
most demanding clinical laboratories.
Specific Performance Characteristics
Reportable Range (NCCLS EP6-P)
– Reportable range is dependent on
the sample to reagent volume used. The
DCL Microalbumin procedure described,
run on a Roche/Hitachi®
717 analyzer, gives a reportable range of 5 – 300 mg/L
(0.5 – 30.0 mg/dL).
Accuracy (NCCLS EP9-P)
–
The performance of DCL Microalbumin
(y) was compared to the performance of
another commercially available method (x)
on a Roche/Hitachi 717. Urine samples
from sixty-four (64) patients, with
concentrations ranging from 0 – 197 mg/L (0.0 –
19.7 mg/dL), were tested. This
comparison study yielded a correlation coefficient
of 0.9981, with a resulting linear regression
equation of y = 0.95x + 0.36 mg/L (0.036
mg/dL).
Precision (NCCLS EP5-T2)
–
Data was collected on two levels of
standard materials with Microalbumin concentrations
of 7.9 mg/L and 54.9 mg/L (0.79 and 5.49
mg/dL). The resulting Within-Run SD’s were
0.34 mg/L and 1.61 mg/L (0.034 and
0.161 mg/dL) respectively, generating
Within-Run CV%’s of 4.3 and 2.9. The
resulting Total SD’s were 0.47 mg/L and 2.00 mg/L
(0.047 mg/dL and 0.200 mg/dL)
respectively, generating Total CV%’s of 6.0 and
3.6.
Ordering Information
|
PRODUCT
|
CATALOGUE
NUMBER
|
PACKAGING
CONFIGURATION
|
| Microalbumin |
252-20 |
4 x 20 mL Buffer Reagent;
2 x 10 mL Antibody Reagent |
|
SUPPORTING
PRODUCTS |
Microalbumin Urine
Controls |
SM-252 |
4 x 8 mL |
Microalbumin
Multi-Calibrator Set |
SE-252 |
6 x 1 mL |
REFER TO PACKAGE INSERT AND/OR
MSDS FOR ADDITIONAL TECHNICAL
INFORMATION
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are trademarks of their respective
holders.
© Diagnostic Chemicals Limited
2005. All rights reserved.
