| Field code | NBT4 |
| Field description | Number of tubes for the fourth product |
| Field type | Numeric Length: 2 |
| Field rule | See note 2 in the appendix |
| Dictionary field | Blood sample requirements (amount) (The amount (volume) of peripheral blood samples) |
| EMDIS messages |
SMP_REQ |
| WMDA XML fields related to dictionary field |