PhiX loading concentrations for validation runs on Illumina sequencing platforms

A PhiX validation run confirms proper hardware and software performance of the instrument. The Illumina PhiX control library is a well-balanced genome with relatively equal representation of A, T, G, and C nucleotides. PhiX lacks an index and is not an appropriate tool for assessing Index Read performance.

It is important that a PhiX control run fall within optimal cluster densities for each platform, as listed in the following table.

Platform

Optimal Loading Concentration

Optimal Raw Cluster Density

iSeq 100

100 pM

N/A**

MiniSeq

1.4 pM

170-220K clusters/mm2

MiSeq v2 reagents

12.5 pM

1000-1200K clusters/mm2

MiSeq v3 reagents

20 pM

1200-1400K clusters/mm2

NextSeq 500/550 High Output reagents

1.5 pM

170-220K clusters/mm2

NextSeq 500/550 Mid Output reagents

1.5 pM

170-220K clusters/mm2

NextSeq 1000/2000

650 pM

N/A**

HiSeq 2000/2500 High Output v3

12 pM

750-850K clusters/mm2

HiSeq 2000/2500 High Output v4

18 pM

950-1050K clusters/mm2

HiSeq 2500 Rapid Run v2

12 pM

850-1000K clusters/mm2

HiSeq 3000/4000

2-3nM*

N/A**

NovaSeq 6000 - Standard Workflow

250 pM***

N/A**

NovaSeq 6000 - XP Workflow

100 pM***

N/A**

NovaSeq X - 1.5B/10B

140 pM***

N/A**

NovaSeq X - 25B

140 pM***

N/A**

*Nondenatured pre-ExAmp concentration **Patterned flow cells consist of a nanowell with ordered wells, no variation in reported cluster density from run to run ***Final loading concentration

Run length and parameters vary depending on troubleshooting needs, however, Read 1 and 2 must have at least 26 cycles to generate quality scores.

For further information about preparing PhiX for sequencing, see the following documents.

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