### Technical

##### Calculation of ELISA results by two software
source：Technical divisiondate：2022-05-11views：722

Method 1: Use OriginPro 2021 software to calculate the ELISA results of the competition kit

Step 1: We take PG(Progesterone) ELISA Kit as an example

Copy and paste the data of the standard curve into the following table.

Press Ctrl+A to select all and then click in order:Analysis---Fitting---Nonlinear Curve Fit---Open Dialog...

In the Function Selection tab, set the Category parameter to Statistics

Set the Function parameter to Logistic

Check Find X from Y in the Find X/Y tab, then click the Fit button

The horizontal and vertical coordinates select the Log10 parameter,

Pay attention to the selection of the upper and lower limit values of from / to, click OK when finished.

The final result is calculated. Since the OD value of the competition method is inversely proportional to the sample concentration, there is no need to subtract the blank well background value. If it is a sandwich method kit, then need to subtract the background value in excel in advance and then follow the tutorial to calculate.

Method 2: Use Curve Expert1.4 software

Drawing of the standard curve

Various drawing software can be used to draw the ELISA standard curve. Taking the "Curve Expert1.4" software as an example below, the method for drawing the ELISA standard curve is as follows;

1. Start "Curve Expert"

2. Enter the OD value of the standard product on the X axis (input OD-blank value for the double antibody sandwich), and enter the corresponding concentration value on the Y axis, as shown in the figure:

1. Click the [Run] button, the following dialog box will appear

1. Click the [ok] button, the following two dialog boxes will appear, close the last dialog box

5. Some curve names will appear in the upper right corner of the dialog box. Click the curve names in sequence starting from "1", and the corresponding fitted curve will appear in the lower right corner.

(Generally choose the first polynomial fit)

6. Select the curve with the best fit of ELISA according to the fitted curve and double-click, the following dialog box will appear:

Note: Choose the curve equation with the best coefficients (i.e. the "r" value) for the calculation. in the following dialog

There is an "r" value in the upper right cornerWhen the "r" value is closer to 1, the better the fit

1. Press [Ctrl] key + [L] key, the following dialog box will appear:

1. Enter the standard OD value and click [Calculate] to get the actual content of the protein to be tested (the sample is diluted N times, and the calculated value should be multiplied by N).
2. If you want to get the equation of the ELISA fitting curve, right-click on the blank space of the dialog box in step 6 and select "Information"

1. Get the following dialog box: Click "Copy"

Paste it where you need it to get the following data:

Rational Function: y=(a+bx)/(1+cx+dx^2)

Coefficient Data:

a = -21.531017

b = 212.05019

c = -0.24054479

d = 0.018060778

11. Modify the height of the X, Y coordinate axes and related properties in the drawing

Select the second row of "Graph Properties" in the figure shown in step 9, and click OK to save after modification.