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KRISHILISATM
ELISA Kits for Agri Sciences
KRIBIOLISATM
ELISA Kits for Biopharmaceuticals
Cytokine
ELISA Kits for Research & Drug Discovery
KRISHGEN
ELISA Kits / Immunoassays now come with the
GOLD QUALITY RING.
This ring with the five stars symbolize that all our kits are validated for
a number of internal specifications including sensitivity, specificity, spike &
recovery rate, inter/intra-assay variability,
wet/dry validation studies, accelerated stability
studies.
It is an assurance that our kits
maintain a certain quality standard in line with our
reputation for technical support.
Our ELISAs are manufactured with care
to uphold the highest standard of quality. We use
the best of components for our kits.
Look Inside Our Kits -
• Corning Costar™ Microtitre Plates / Stripwells.
• Antibodies from reputed manufacturers in USA.
•
Immunoassay Components from world leader - Surmodics
Inc., USA
•
Eppendorf™ Pipettes for dosing accuracies.
• Validated Studies
• Quality Control for each manufactured lot.
Preliminary specifications defining
acceptable ranges for the parameters indicated
herein below are established for all our kits. These
parameters are tracked day-to-day, run-to-run, and
operator-to-operator, over a schedule defined
in-house. Recommended assay characteristics include
absorbance of a zero concentration standard; factors
which describe the calibration such as displacement
(B/Bo ratios) for each standard and statistical
description of the calibration curve such as
coefficient of correlation, slope and/or intercept;
and recovery of results on control samples. It is
important to be able to relate the specifications
for a parameter to expected reliability of the
result. Our in-house standard is defined by a
coefficient relationship of over and above r=0.990
for all our immunoassays.
The data is graphically
plotted presenting the quality control data. The
concept of control charts was first developed in
1934 by Walter Shewhart to describe output of a
manufacturing process. They can be useful in
demonstrating statistical control monitoring the
measurement process, diagnosing measurement
problems, and documenting measurement uncertainties.
Control charts consist of some measured parameter or
statistic such as a mean or a precision estimate
plotted sequentially or as a function of time.
To determine if a sample may contain interfering
substances, spike / recovery tests are performed. A
sample may interfere during the color development
step of an ELISA. Potential interferences of this
type were further investigated by spiking an aliquot
of the suspect sample with a known concentration of
the antigen/protein. A poor recovery of the spike,
either increased or decreased, would suggest the
presence of interference. Typically, results outside
a range of 80 to 120% recovery can be used to
identify interferences but each lab should establish
their own range based on their experience. Our tests
indicated recoveries of around 80% - 90% and above
on different sample matrices.
Calculation Of B/Bo %
1. Determine the mean O.D. for each pair of
duplicate wells.
2. Derive B/B0 for each standard, control as
follows:
NSB-B
B/B0 % = ------------ x 100
NSB-B0
B = mean O.D. of each pair of wells,
B0= mean O.D. of ‘0’ std. wells
B/Bo v/s concentration of antigen/protein is plotted
and used to interpret all data.
1. Sensitivity :
a) Limit Of Detection: It is defined as the lowest
detectable concentration corresponding to a signal
of Mean of ‘0’ standard plus 2 * SD.
10 replicates of ‘0’ standard are evaluated.
b) Limit of Quantitation: It is defined as the
lowest concentration for which Coefficient of
Variation is <20%.
2. Specificity / Cross Reactivity :
Specificity of an analytical method is defined as
its ability to measure an analyte accurately in the
presence of interference.
3. Precision : Precision is defined as
the percent coefficient of variation (%CV) i.e.
standard deviation divided by the mean and
multiplied by 100. Assay precision was determined by
both intra (n=5 assays) and inter assay (n=5 assays)
reproducibility on two pools with low and high
concentrations. While actual precision may vary from
laboratory to and technician to technician, it is
recommended that all operators achieve precision as
per these design goals before reporting results.
4. Recovery by Spiking : In spike and
recovery, a known amount of analyte is added
(spiked) into the natural test sample matrix and its
response is measured (recovered) in the assay by
comparison to an identical spike in the standard
diluent.
5. Wet and Dry Assay Validation :
Assays Correlation are used with Coefficient (r),
Intercept (A) and Slope (B)
6. Accelerated Shelf Life Study :
Absorbance at Day 1 and Day 60 is used at elevated
time temperature of 45°C to measure the stability of
our kits and validate our expiration dates.
Conclusion :
The emphasis of this validation has been to offer
different aspects to enable user to fit the same
into their overall quality control program. An
overall approach to total quality has been detailed
elsewhere (Juran & Gryna, 1988). Further, the
quality control program needs to fit into a larger
context which is dependent on the organization in
which it is being conducted. There are many factors
at work such as the influence of external
requirements including GLP's and project related
needs, the organizational policy on quality control,
and other internal needs. A strong quality control
program will include aspects which address these
needs.
To remove sources of error and increase the
reliability, greater automation can be applied to
immunoassays. In the clinical application of
immunoassay these sources of error have now been
identified (Holzel, 1991) and the use of automation
to control many of the variables is being routinely
employed.
talk to
our technical team to learn more on our quality.
Email:
sales@krishgen.com
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