2451: Chimerism Essential Data

The Chimerism Essential Data (2451) is intended to capture the results of chimerism studies completed in the reporting period. This form will come due at the Day 100, Day 180, if applicable, and Day 365 timepoints when it is reported chimerism studies were completed in the reporting period for recipients on the Transplant Essential Data (TED) and Comprehensive Report Form (CRF) track for the following:

Transplant Essential Data (TED)

• Recipients who receive an allogeneic transplant using cord blood units
• Allogeneic recipients who primary disease for infusion is non-malignant
  

Comprehensive Report Form (CRF)

• Recipients who receive an allogeneic transplant using cord blood units
• Allogeneic recipients whose primary disease for infusion is non-malignant
• Allogeneic recipients whose primary disease for infusion is malignant
  • The Chimerism Essential Data (2451) will only come due if chimerism studies were reported on the Day 100 and 1 Year Post-Infusion Follow-Up (2100) Form

Links to Sections of Form:
Q1 – 3: Chimerism Studies

Manual Updates:
Sections of the Forms Instruction Manual are frequently updated. The most recent updates to the manual can be found below. For additional information, select the manual section and review the updated text.

To reference the historical Manual Change History for this form, reference the retired manual section on the Retired Forms Manuals webpage.

Date	Manual Section	Add/Remove/Modify	Description
10/24/2025	2451: Chimerism Essential Data	Add	Instructions added on how to report multiple other cell types in Q2 : If multiple ‘other’ cell types were assessed and are being reported, add an additional instance in the FormsNet3SM application.
10/24/2025	2451: Chimerism Essential Data	Add	Reporting Results for Multiple Donors blue box added to the chimerism results section: Reporting Results for Multiple Donors: When there are multiple donors (either from a prior infusion or the current infusion), chimerism results must be entered for every cell type assessed, for each donor, even if the results are ‘0.’.
10/24/2025	2451: Chimerism Essential Data	Add	Clarified when the 2451 comes due for recipients with malignant diseases on the CRF track: Recipients who receive an allogeneic transplant using cord blood units Allogeneic recipients whose primary disease for infusion is non-malignant Allogeneic recipients whose primary disease for infusion is malignant The Chimerism Essential Data (2451) will only come due if chimerism studies were reported on the Day 100 and 1 Year Post-Infusion Follow-Up (2100) Form
10/24/2025	2451: Chimerism Essential Data	Add	Due to Fall Release, introduction updated to clarify when 2451 will come due: The Chimerism Essential Data (2451) is intended to capture the results of chimerism studies completed in the reporting period. This form will come due at the Day 100, Day 180, if applicable, and Day 365 timepoints when it is reported chimerism studies were completed in the reporting period for recipients on the Transplant Essential Data (TED) and Comprehensive Report Form (CRF) track for the following: Transplant Essential Data (TED) Recipients who receive an allogeneic transplant using cord blood units Allogeneic recipients whose primary disease for infusion is non-malignant_ Comprehensive Report Form (CRF) Recipients who receive an allogeneic transplant using cord blood units Allogeneic recipients whose primary disease for infusion is non-malignant Allogeneic recipients whose primary disease for infusion is malignant
7/25/2025	2451: Chimerism Essential Data	Add	Version 1 of the 2451: Chimerism Essential Data section of the Forms Instructions Manual released. Version 1 corresponds to revision 3 of the Form 2451.

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CIBMTR® (Center for International Blood and Marrow Transplant Research) is a research collaboration between the Medical College of Wisconsin and NMDP.