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# How to Calculate Delta Delta CT in Excel (With Easy Steps)

In this article, I will show how to calculate delta delta CT (Cycle Threshold) in Excel by using 4 easy steps. When you work on an Excel worksheet, you may need to do a variety of work.  Delta delta CT is a very common expression in Excel works. Delta delta CT is used in Polymerase Chain Reactions (PCR).  In this article, I will show you four practical steps to calculate delta delta CT in Excel. This will help you to increase your Excel skills.

## What Is Delta Delta CT?

A relative quantification technique is a real-time PCR (Polymerase Chain Reaction). Every study must contain a baseline or calibrator sample to which all other samples are compared as well as at least one endogenous control gene to standardize samples. CT (cycle threshold), dCT (delta Ct), and ddCT are the terms used to express real-time PCR results (delta delta CT). The cycle threshold is the cycle number at which the fluorescence for the reaction well reaches the threshold value (CT).

## Step-by-Step Procedures to Calculate Delta Delta CT in Excel

This is the dataset I am going to use in this article for every step. The database contains five columns, B, C, D, E, and F called Sample, Ct 1, Ct 2 for Housekeeping Gene, and Ct 1, Ct 2 for Gene of Interest. Hence, follow the steps one by one. Moreover, I have added the necessary illustrations for every step for your better understanding. ### Step 1: Getting Average CT

In this step of this article, I will work to get the average ct of my dataset. This is the first step of the procedures to calculate delta delta CT in Excel. Follow the procedures given below.

• First, add two columns in E and H called the Average CT of both. The first one is for the Housekeeping Gene and the second one is for the Gene of Interest. • Then, write down the following formula in cell E6 and press Enter.
`=AVERAGE(C6:D6)`

We used the AVERAGE function to get the average of CT 1 and CT 2. • This Enter command shows the average of Control 1 for Housekeeping Gene.
• Then, Fill-Handle to copy down the formula from E6 to E11. • As a result, this command will show the Average CT of the Housekeeping Gene. • After that, to get the Average CT of the Gene of Interest, Copy the following formula in the H6 cell and press Enter.
`=AVERAGE(F6:G6)`

The formula will also return the average of CT 1 and CT 2. • After copying down the formula from H6 to H11 cell, Excel will calculate the Average CT of the Gene of Interest portion. ### Step 2: Calculating Delta CT

In this second part of the procedure of calculating delta delta CT in Excel, I will calculate the delta CT here, Moreover, the average of delta CT will also be calculated here. So follow the procedure step by step patiently.

• First, add a new column in the dataset called delta CT. • Then, in the I6 cell, write down the following formula and press Enter.
`=H6-E6`

We used this formula to get the delta CT.

• Then, press Enter. • After this command, the delta CT for Control 1 will appear and the value is 13.38. • Meanwhile, copy down the formula from I6 to I11. • Then, I created a new portion to show the average delta CT. • In the I13 cell, write down the following formula and press Enter.
`=AVERAGE(I6:I8)`

We used this function to get the average of 13.38, 13.60, and 13.68.

• Then, press Enter. • As a result of this command, the average delta CT is calculated. ### Step 3: Computing Delta Delta CT

In this third step, I will calculate delta delta CT in Excel. Follow the following procedures. The steps are very easy. Hopefully, you will enjoy it.

• First, add a new column in the J column called delta delta CT. • Meanwhile, copy down the following formula in the J6 cell and press Enter.
`=I6-\$I\$13`

This will return the delta delta CT.

• After that, press the Enter button. • As a result of this operation, you will find the effect of delta delta CT as -0.18. • After applying flash fill in the J column, Excel will calculate the total result of delta delta CT for every sample. ### Step 4: Final Result

In this section of this article, You can see the final result in the picture below.

• Excel has calculated delta delta CT  with the help of simple mathematical operators and Excel functions. Hence, this is how you can calculate delta delta CT in Excel with some easy and simple steps.

## Things to Remember

• You should bear in your mind that the procedure is quite lengthy and a handful amount of calculations are used. So, be careful at the time of applying formulae.

## Conclusion

In this article, I have tried to explain how to calculate delta delta CT in Excel. I hope, you have learned something new from this article. Now, extend your skill by following the steps of these methods. You will find such interesting blogs on our website Exceldemy.com. I hope you have enjoyed the whole tutorial. If you have any queries, feel free to ask me in the comment section. Don’t forget to give us your feedback.

## Related Articles #### Souptik Roy

Hello there. This is Souptik Roy. I graduated from Naval Architecture & Marine Engineering department. I am trying to explore the world of Microsoft Excel and want to increase my analytical power apart from my Engineering degree, as I have a curious mind. this is why I am trying to learn Excel Operations and write articles to help others.

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