COVID identification in primary care - antigen test negative

Coding system
CTV3 (Read V3) with TPP extensions
Codelist ID


Codes indicating COVID-19 antigen test negative (1 of 7 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 "antigen test negative" was then performed following review of terms by six OpenSAFELY team members (including epidemiologists, clinicians, statisticians and infectious disease modellers).


Signed off by

  • Kevin Wing, LSHTM (June 24, 2020)
  • Alex Walker, EBM Datalab (June 24, 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
Y20d2 SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) RNA (ribonucleic acid) detection result negative
Y22a2 Coronavirus disease 19 caused by severe acute respiratory syndrome coronavirus 2 excluded by laboratory test (situation)
Y23f4 SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) detection result negative

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