= Read Codes

Read codes come in two flavours: version 2 and Clinical Trials Version 3 (CTV3).

Both can be downloaded from [[https://www.uktcregistration.nss.cfh.nhs.uk/trud3|TRUD]].

== Clusters

Read codes can be clustered into various groups for particular diseases.  The details of these clusters can be downloaded from the [[http://www.pcc-cic.org.uk/article/qof-business-rules-v27|QOF Business Rules]] page.  '''Note that the versions change quite regularly, so make sure you have the latest version.'''

Here is a [[http://www.hscic.gov.uk/media/1577/Reading-and-Understanding-QOF-Business-Rules/pdf/qof-bus-rules.pdf|nice explanation of how to interpret the business rules]].