EBMcalc Medical Calculator

COVID-19 Symptom-Based C19 Rule for Diagnosis

Symptoms Loss of taste or smell (2 points) Cough and fever (1 point) Chest tightness or wheezing (-1 point)

Important: Inputs must be complete to perform calculation.

Total Criteria Point Count:

C19 Rule Interpretation

3 points:

LR+ 15 for diagnosis of COVID-19

2 points:

LR+ 4.2 for diagnosis of COVID-19

1 point:

LR+ 1.2 for diagnosis of COVID-19

0 points:

LR+ 0.7 for diagnosis of COVID-19

-1 points:

LR+ 0.1 for diagnosis of COVID-19

Data action

Include literature references: Yes No

Notes

When the odds (by prevalence) of COVID-19 is known, these odds may be multiplied by the calculated LR+ to obtain the post-test odds of COVID-19 in individuals with the symptoms above.
LR+: likelihood ratio of a positive test.

References

Smith DS, Richey EA, Brunetto WL. A Symptom-Based Rule for Diagnosis of COVID-19. SN Compr Clin Med. 2020 Oct 24:1-8. PubMed ID: 33134843

Associated HCC ICD10-CM codes

B97.29

Other coronavirus as the cause of diseases classified elsewhere

D68.69

Other Thrombophilia (COVID-19 associated hypercoagulability)

D68.8

Other Specified Coagulation Defects (COVID-19 associated coagulopathy)

J12.82

Pneumonia due to coronavirus disease

M35.81

Multisystem inflammatory syndrome.

M35.89

Other specified systemic involvement of connective tissue

U07.1

COVID-19

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