GP practices
NHS Digital corporate reference data is used to create a reference table in the staging database. All distinct entries in that table are brought in the query, entries are not filtered, and information from this table is used only in the event of receiving a fit note submission from a GP practice.
The practice code entry in the fit note is checked against the table, and that the practice does not have a close date.
If both criteria pass the fit note is processed. If any are rejected, this is included in the data quality report.
Duration calculation
If Indefinite is supplied: The duration is Indefinite.
If Indefinite is not supplied, and
- Days + (Days in weeks) + (Days in months) >= (EndDate – StartDate) : The Duration is Days + (Days in weeks) + (Days in months)
- (EndDate – StartDate) >= Days + (Days in weeks) + (Days in months): The Duration is (EndDate – StartDate)
Code mapping to ICD10
Definition: fit note diagnostic codes need to be mapped to ICD10 and aggregated to a chapter level, and up sub-chapter codes. The extracted data includes diagnostic codes in the practice’s coding system. These are read clinical codes version 2 (Read) and clinical terms version 3 (CTV3) or SNOMED which is in the process of replacing Read and CTV3.
Business rule: These codes are mapped to the ICD10 coding system, using NHS Digital reference mapping tools.
Standards: NHS Digital reference mapping tools. Codes are updated by NHS Digital on a 6-monthly basis, and suppliers are expected to update their systems to incorporate new codes. Historical codes are not deleted.
NIS-retired codes: If data contains retired codes, as is likely for the historical data, where possible these will be mapped to the relevant ICD10 chapter even if mapping at sub-chapter level is not possible. It is not clear at the time of writing whether it is possible to obtain information on which ICD10 chapter the retired code used to map to.
Multiple submissions
It is recognised that practices change GP practice systems from time to time. During migration from the old to the new system, it is possible that systems are run in parallel, and data can exist in both systems and therefore be extracted by two (or more) different suppliers for the same practice code.
All extracts will be accepted.
Checks are made in the staging process for any duplicate Unique IDs. The first Unique ID is accepted; any subsequent duplicate Unique IDs is rejected and stored in the rejected table.
The quality report indicates on a weekly basis how many multiple submissions have been received for a given practice code.
Duplicate IDs
Duplicate Unique IDs are checked at staging, against the existing database. As this will affect the speed performance of staging, the check will be limited to the rolling last month of fit notes.
Linked fit notes
Definition: Fit notes that are linked with the same linking ID are considered to be linked fit notes.
Assumption: We believe that the same linking ID will be present for consecutive, as well as non-consecutive, fit notes.
Business rule: For calculating duration of a linked episode, two or more fit notes will be considered linked if:
They have the same linking ID.
They are consecutive, that is,
- the statement date of the newer fit note is the within the period of the previous fit note, or
- the statement date is the same as the end of the previous fit note, or
- the statement date falls within 7 days of the end of the previous fit note.
If two fit notes have the same linking ID, but are more than 7 days apart, (end date and statement date) they will be considered separate episodes.
Where a patient moves practices, the linking ID will follow the patient if the fit note data is transmitted successfully by GP2GP record transfer. In these cases, display of linked fit note data will take the GP Practice ID from the most recent individual Med3 in the episode.
In a series of linked fit notes, the gender and diagnosis code are taken from the first fit note in the series. The GP practice code is taken from the last fit note.