Table 1.

Interpretation of dengue diagnostic test results among patients with COVID-19

Patients (N = 42)	RT-PCR/NS1 antigen	IgM RDT or ELISA	IgG RDT	IgG ELISA	Interpretation
2	NS1 negative	Negative	Negative	Negative	Never infected by DENV
33*	NS1 negative	Negative	Negative	Positive	Past infection by DENV
4	RT-PCR and NS1 negative	Positive (no follow-up IV increase)	Negative	Positive	Recent secondary DENV infection
		#1: 4.8 to 4.1		#1: 9.5 to 9.2
		#2: 2.8 to 0.5		#2: 8.5 to 8.1
		#3: 1.6 to 0.8		#3: 4.8 to 6.4
		#4: 3.7 to 1.6		#4: 10.2 to 9.5
3	RT-PCR and NS1 negative	Positive (no follow-up IV increase)	Positive faint	Positive	Very recent secondary DENV infection, with high-titer IgG
		#1: 3.8 to 3.8		#1: 17.1 to 16.6
		#2: 2.5 to 1.1		#2: 12.3 to 11.5
		#3: 1.6 to 1.5		#3: 12.5 to 12.3

DENV = dengue virus; IV = index value; RDT = rapid diagnostic test.

^*Ten patients in this group did not have follow-up sera. For patients with positive IgM and IgG, admission and follow-up IV are shown. Changes in both IgM and IgG interpretation were not noted in follow-up sera. There were no cases of current dengue coinfection.