In response to a query by Kenneth Norrie regarding software for the
collection and analysis of ELISA data, the following describes an MS-DOS
based package with several desirable features. For clients with specific
analytical needs, arrangements may be made for software customization.
ELISA! provides an integrated environment for raw data collection,
storage and analysis. By offering a number of specialized features as well
as a high degree of versatility, ELISA! will be of value to the high volume
analytical lab as well as the research lab. The program employs a pull-down
menu user interface which is not only easy to master but also makes for a
fast and efficient means of executing the various commands and features
offered by ELISA!. The ELISA! environment provides complete control over
data collection, storage, retrieval and analysis. The data collected from a
single multi-well plate are stored as a separate record, together with a time
and date stamp and a one line descriptive title, within a data file which may
hold many tens or hundreds of such records. Individual data records may
be deleted, moved from one file to another, printed to the printer or an
ASCII character text file. Data records printed to ASCII files may be directly
imported into spreadsheet programs such as Lotus 123 or Symphony for
further analysis. In addition some common DOS file operations including file
copying, file deletion, file renaming, directory listings and setting the logged
directory may also be performed.
Data Reduction Procedures Include
Producing a sorted list (descending order) of well absorbance
values and associated well ID's from one or more plate records. Displaying
a subset of plate absorbance values which are greater than a given
threshold value. Summary statistics (mean, standard deviation) or a
frequency distribution histogram can be generated for those values either
above or below the chosen threshold value.
A quick sketch of one or more selected data ranges within a plate
record may be easily produced for output to an Epson FX compatible dot
matrix printer. The different data ranges may be displayed using various
different symbols, line types and line thicknesses, and as well there are
options for various types of curve smoothing (point-to-point, cubic spline,
Bezier polynomial).
Summary statistics (mean and standard deviation) of a selected
data range within an individual plate record.
A frequency distribution analysis of absorbance values from one or
more plate records can be performed. The number of intervals as well as
the upper and lower range limits may be individually specified or determined
automatically by the program. A textual report as well as a histogram plot
are produced.
Analysis of antibody titration and antigen competitive inhibition
experiments using selected data from one or more plate records. Data from
such experiments may be fitted using a non-linear regression algorithm to
either pre-set functions or to any equation the user desires. Estimates of
antibody affinity (defined as the dilution of antibody giving half-maximal
binding, T50) and Amax are generated for titration experiments while
estimates of the I50 concentration (defined as the concentration of
competing agent which produces a 50% inhibition of observed antibody
binding) are produced for inhibition experiments.
For screening suspect samples, the pathoscreen analysis module
allows reporting of sample values greater than a certain number of times
the mena OD value(s) of one or more blank control samples. This module
makes use of template specification records which identify the locations of
standards, unknowns and blanks on the plate, and outputs a report
including summary statistics to either the monitor, printer or a disk file. In
addition, the results can be output to a comma delimited, quoted string, text
file suitable for importation into a database management application such
as Paradox.
For ELISA experiments involved in clinical or field testing the
program provides a quantitative analysis routine which calculates
concentrations of unknowns based on standards included within the
experiment. This routine utilizes definition plate records which specify which
wells in the plate contain standards (and what their concentrations are),
unknowns to be tested or blank wells (undefined wells will not be included
in the analysis). A single definition record may be used to process one or
more data records with output directed either to the monitor, printer or a
disk file.
In addition, ELISA! allows for some simple mathematical operations
to performed on one or more plate records. This includes plate subtraction,
division and multiplication. In these routines all of the absorbance values
from one or more plate records may be subtracted from; divided by; or
multiplied by the corresponding well absorbance values from a second list
of plate records.
This version of ELISA! has been tested with the full range of
Titertek Multiskan MC and MCC plate readers distributed by Flow Scientific
as well as the Bio-TEK 312, Dynatech MR5000/7000, BioRAD 450, and
Molecular Devices emax readers and found to work flawlessly. The
program will also accommodate a limited degree of user defined
customization with respect to collection parameters, which should enable it
to operate with other plate readers. Failing this, any necessary program
modification should be a relatively simple matter and will be accommodated
upon request.
Leading Edge Research
758 Newport Avenue
Victoria, BC, Canada V8S 5C9
Tel: (604) 598-0677
Fax: (604) 363-6661
Donald MacKenzie
(mackenzied at em.agr.ca)
