# Input quantity for Illumina DNA PCR Free libraries

**How much DNA is the optimal for Illumina PCR free kit?**\
High quality libraries will be generated from 25 ng to 2000 ng. For optimum performance, and when sample amount permits, Illumina recommends using saturating amounts of DNA (at least 300 ng for gDNA and recommended raw sample volumes for integrated extraction options).

**What is the consequence of using lower or higher than the recommended input?**\
At lower input amounts, reduced yield and smaller insert size may be observed. Input greater than 2000 ng has not been tested.

**How far above and below the DNA recommended input has been tested?**\
A range from 25 ng-2000 ng has been tested.

**How should the quality of the input DNA be assessed?**\
Refer to the *DNA Input Recommendations* and *Assess Purity* sections of the [Reference Guide](https://support.illumina.com/downloads/illumina-dna-pcr-free-reference-guide.html).

**What DNA extraction methods does Illumina recommend for input material (for different sample types, blood, saliva, dried blood spots) to the Illumina DNA PCR-Free kit?**\
Refer to the *Supplemental Procedures* section of the [Reference Guide](https://support.illumina.com/downloads/illumina-dna-pcr-free-reference-guide.html).

**Is it possible to increase yield from whole blood or dried blood spots (DBS). Can additional input be used? Can the BLT-PF volume be increased to 15 µl, like in the standard purified gDNA protocol? What about for saliva input?**

It is important to follow the instructions in the protocol; changing the amount of input blood or saliva or changing the amount of BLT-PF will result in compromised protocol performance.

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #3432), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000003432%20-%20Library%20Preparation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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