COVID identification in primary care - suspected covid - isolation code

Coding system
CTV3 (Read V3)
Codelist ID


Codes indicating COVID-19 case (1 of 13 possible types of CTV3 codes that contain information related to COVID-19)


Search of TPP CTV3 codes for terms relating to coronavirus, with additional (manual) check for any missing terms against the SNOMED list of COVID-19 related codes.

Classification as "case" was then performed following review of terms by six OpenSAFELY team members (including epidemiologists, clinicians, statisticians and infectious disease modellers).


Signed off by

  • Krishnan Bhaskaran, LSHTM (July 16, 2020)
  • Laurie Tomlinson, LSHTM (July 16, 2020)

This definition has been computed by taking the manually created full codelist and converting it to a list of rules that define the codelist.

CTV3ID CTV3PreferredTermDesc CTV3Source
Y228f Self-isolation to prevent exposure of community to contagion
Y22a6 Household isolation note issued to patient (finding)
Y22a7 Household isolation to prevent exposure of community to contagion
Y22ac Has National Health Service digital isolation note (finding)
Y22ad Self-isolation note issued to patient (finding)

Codes in the definition are underlined. Codes in the full codelist are in blue. Related codes not in the codelist are in black.