Diarrhea-to-Vomiting Prevalence Ratio (D/V Ratio) During Outbreak of Acute Gastroenteritis

 

diarrhea-to-vomiting ratio = D/V ratio =

= (percentage of patients with diarrhea) / (percentage of patients with vomiting)

 

where:

• Some patients will have both diarrhea and vomiting.

 

Interpretation (Dalton et al, page 12):

• A ratio >= 2.5 suggests an ETEC (enterotoxigenic E. coli) outbreak. This reflects that diarrhea is more common than vomiting. The range (1.3 to 45.5) had a median of 7.1

• A ratio < 2.5 suggests a viral gastroenteritis. The range (0.6 to 5.5) had a median of 1.4.

• Patients with ETEC and a ratio < 2.5 had a median duration of illness > 60 hours (Dalton et al, page 14).

 

Using the data ranges:

Ratio	Interpretation
< 1.3	viral
1.3 to 2.49	probably viral
2.5 to 5.5	probably ETEC
> 5.5	ETEC

 

Performance:

• A cutoff >= 2.5 has a sensitivity of 82% and specificity of 92%.

 

Limitations:

• The interpretation may be misleading if the number of affected patients is low or if the total number of people with diarrhea and/or vomiting is low.