The NHS NUMBER, the primary identifier of a PERSON, is a unique identifier for a PATIENT within the NHS in England and Wales.

This will not vary by any ORGANISATION of which a PERSON is a PATIENT.

It is mandatory to record the NHS NUMBER. There are exceptions, such as emergency care, sexual health and major incidents, as defined in existing national policies.

The NHS NUMBER is 10 numeric digits in length. The tenth digit is a check digit used to confirm its validity. The check digit is validated using the Modulus 11 algorithm and the use of this algorithm is mandatory. There are 5 steps in the validation of the check digit:

**Step 1** Multiply each of the first nine digits by a weighting factor as follows:

**Digit Position**

(starting from the left) Factor:

1 | 10 |

2 | 9 |

3 | 8 |

4 | 7 |

5 | 6 |

6 | 5 |

7 | 4 |

8 | 3 |

9 | 2 |

**Step 2** Add the results of each multiplication together.

**Step 3** Divide the total by 11 and establish the remainder.

**Step 4** Subtract the remainder from 11 to give the check digit.

If the result is 11 then a check digit of 0 is used. If the result is 10 then the NHS NUMBER is invalid and not used.

**Step 5** Check the remainder matches the check digit. If it does not, the NHS NUMBER is invalid.

Further guidance is available from the NHS Digital website at: NHS Number.

Note:

This was e-GIF approved for use in NHS England.

e-GIF and the Government Data Standards Catalogue **have been archived** and are available for reference only.

**This attribute is also known by these names: **

Context | Alias |
---|---|

plural | NHS NUMBERS |