2.3.1 Symptoms 

Symptoms represent physical or mental features which are regarded as an indication of a condition or disease, particularly those features that are apparent to the patient. This SNOMED CT subset of COVID-19 symptoms has been developed based on a range of literature, including relevant articles found in Pubmed ¹, research performed by Kings College London ² , and a review of COVID-19 data collection forms (e.g. ³). Please note that this subset includes the concept  84387000 | Asymptomatic (finding)| , which can be used to represent the absence of symptoms.

2.3.2 Severity 

Severity represents the quality of the condition - for example,  24484000 | Severe (severity modifier) (qualifier value)| . Severity may be recorded for each symptom, or as a general statement of their disease state ⁴. 

2.3.3 Clinical Measurements 

Clinical measurements involve the performance of physiological tests to diagnose and refine therapeutic management of an already established disease. The following clinical measurements (and related observables) can be used in the assessment of a COVID-19 patient.

2.3.4 Clinical Examination Findings 

Clinical examination findings are the result of measuring, questioning, evaluating, or otherwise examining a patient in healthcare. The following clinical findings are positive or negative indications that signs are present in a COVID-19 patient.

2.3.5 Diagnosis and Certainty 

A diagnosis is the identification of the nature of the illness, based on an examination of the symptoms, observations, measurements, test results and other investigation results. The following subset includes a range of diagnoses directly related to COVID-19.

To represent the certainty of a positive COVID-19 diagnosis, the following subset may be used in conjunction with a diagnosis of  840539006 | COVID-19| .

To represent the certainty of the absence of COVID-19, the following subset may be used in conjunction with a diagnosis of  688232241000119100 | Disease caused by severe acute respiratory syndrome coronavirus 2 absent (situation)| .

2.3.6 Clinical History 

The clinical history concepts are used to record information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information, with the aim of obtaining information useful in formulating a diagnosis and providing medical care to the patient.

2.3.7 Secondary Conditions and Complications 

A secondary condition is any additional health condition that occurs as a result of the natural progression or expected outcome of the primary condition. A complication is "a disorder caused by another disorder, procedure or event, which is not a natural progression or expected outcome of its cause ⁵.

The following subset includes SNOMED CT clinical findings that may be recorded as either secondary conditions or complications ⁶. Clinical judgement is required to determine whether these conditions are expected outcomes or unexpected complications of COVID-19. 

2.3.8 Potential Risk Factors 

Potential risk factors are the patient conditions which may influence the course or outcomes of the COVID-19 disease. The following clinical findings may be recorded as potential risk factors^3 7 8.

Similarly, procedures performed on the patient within a clinically relevant timeframe may also influence the course or outcomes of the COVID-19 disease. The following procedures may be recorded as potential risk factors ⁸.

2.3.9 Comorbidities 

Comorbidities are additional medical conditions of concern. The following SNOMED CT subset can be used to record comorbidities.

2.3.10 Exposure 

An exposure event is when an individual comes into close contact with an infected person's contaminated droplets, carried in the air or on contaminated hands, surfaces or other objects. The subset below includes SNOMED CT events for recording exposure to COVID-19.

An exposure finding is the result of an observation or evaluation that relates to the patient's exposure to an infection. The subset below includes SNOMED CT findings relating to COVID-19 exposure.

2.3.11 Covid-19 and Viral Co-Infections 

The following organism should be used when recording the organism causing COVID-19 infections.

The following organisms can be used to record the cause of related viral co-infections.

Footnotes