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What is the Undiagnosed Diseases Network (UDN)?

The UDN is a research study funded by the National Institutes of Health Common Fund. The UDN is made up of clinical and research centers across the United States working to improve diagnosis and care of patients with undiagnosed diseases.

Who is eligible?


  • The applicant does not have a diagnosis that explains the objective findings.
  • The applicant (or legal guardian) agrees to the storage and sharing of information and biomaterials in an identified fashion amongst the UDN centers, and in a de-identified fashion to research sites beyond the network.


  • The applicant has a diagnosis that explains the objective findings.
  • Review of the records suggests a diagnosis and further evaluation is deemed unnecessary.
  • The applicant is too seriously ill to travel safely to the UDN site.

How do I apply?

See application instructions.

I'm a physician. How do I refer a patient?

See instructions on how to refer a patient.

I've been asked to participate as a family member, what do I do?

Thank you for considering participation. Please read instructions.

If I apply to the Undiagnosed Diseases Network, will I be assigned to Stanford?

Maybe. The site designation depends on several factors including location and interest. You can request the Stanford site which will be taken into consideration.

What happens if I am accepted to the Undiagnosed Diseases Network?

If you are accepted to the UDN, you will first be contacted and consented to participate in the study. We may also consent members of your family. We will then collect blood samples for genetic testing as well as arrange an in person visit for clinical evaluation and testing. The length of visit and tests to be conducted will vary per case. You will be able to discuss your specific case with the Lead Study Coordinator should you be accepted. Read more about what our research protocol includes.

I submitted an application but haven't heard back yet. Should I call?

Please allow us at least 30 days to review your initial application. If it has been more than this, yes. Contact the UDN Coordinating Center by emailing or by calling 1-844-RINGUDN (746-4836)

I'm having technical trouble submitting my application online. Who do I contact?

Contact the UDN Coordinating Center by emailing or by calling 1-844-RINGUDN (746-4836)

If I am accepted to the Stanford Center for Undiagnosed Diseases with the Undiagnosed Diseases Network, will I be guaranteed a diagnosis?

No. We will do everything possible to identify a diagnosis, but cannot guarantee this outcome. However, we will continue to review your case as new information arises, and it's possible to receive diagnosis later.

I cannot travel. Am I still able to participate?

You must be able to travel to one of the participating sites. We can work with you to minimize travel concerns.

Is a physician's letter of referral required to participate?

Yes. Cases will not be considered without a solid letter of recommendation for participation in the program.

Can I receive care outside of participating in the research network?

Our program is designed to be research and only research participants are eligible to participate. For strictly clinical care you may reach out to Stanford's Lucile Packard Children's Hospital and Stanford Health Care.