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Why did my sample fail sequencing?

A sample may not meet our quality assurance standards and cannot be sequenced for several reasons. In most cases, collecting another sample can resolve the issue.

If you provided a saliva sample, here are some common reasons why it could fail sequencing:

  • Excessive bacteria or contaminants: Too much bacteria or food particles in saliva samples will impact sequencing. Avoid eating or drinking 30 minutes before providing a saliva sample.
  • Incorrect volume: Providing too little or too much saliva can lead to failure. Please follow the instructions and fill the collection tube to the specified marking.
  • White blood cell issues: Certain conditions or treatments (e.g., chemotherapy, bone marrow transplant, hematological cancer) affecting white blood cells, which contain DNA, can prevent sequencing.
  • DNA variations: Underlying DNA variations, like an abnormal number of chromosomes, can cause sample failure.
Important: The Helix lab process is not intended to identify or diagnose the reasons why a sample fails. If your sample doesn’t pass our quality processes, we will let you know that it cannot be sequenced and request a new sample.