| Field identifier | NMBR_MARR |
| Field description | Number of marrow donations |
| Element type | DonItemType |
| Field type | Short |
| Required | No |
| Length | |
| Comment | Number: zero or greater, no decimals |
| Dictionary field | Number of previous HPC donations (Number of times a donor has previously donated either HPC(A) or HPC(M)) |
| EMDIS fields related to dictionary field |
D_NMBR_MARR D_NMBR_PBSC |