Saliva Testing is a Robust Non-Invasive Method for SARS-CoV-2 RNA Detection

Figures & data

Table 1 Demographic Analysis

Sex	Male		Female
Number	50		61
Age interval, years	15–82		18–85
Age median and quartiles, years	44 (26–61)		58 (28.5–68)
Significance, p	0.18
Test Results	Positive	Negative	Positive	Negative
Number	35	15	23	38
Age interval, years	19–82	15–43	24–85	18–61
Age median and quartiles, years	63 (57–71)	27 (25.5–28)	71 (50–79)	30.5 (25.3–48.5)
Significance, p	<0.001		<0.001

Table 2 Comparison of the Results, Obtained Using NP Swab and Saliva Samples

		Saliva Samples
		Positive	Negative
NP swab samples	Positive	57	1
	Negative	1	52

Abbreviations: Ct, cycle of threshold; CE-IVD, agreement with the EU directive “In-Vitro-Diagnostic Medical Devices”; SD, standard deviation.

Figure 1 Correlation between Viral RNA Ct values in matched NP and saliva samples. Only Ct values of the ORF1ab gene were included for NP samples as this gene was detected with all kits and was used for detection in saliva samples as well. “ORF1ab & S” indicates that ORF1ab and S genes were detected in the same channel.

Figure 2 Internal Control RPP RNA Ct values by sample type. The largest group of NP samples that were collected according to the same instructions and matching saliva samples were included.

Figure 3 Distribution of Viral Scores in saliva samples. Viral Scores were obtained normalizing Viral RNA Ct values by control RPP RNA Ct values. Viral scores were classified into three groups: low, medium, and high levels. The cutoffs for classification were defined as mean±0.6475*SD and are shown as dotted vertical lines. Dashed vertical line indicates mean of Viral Scores. Separate observations are shown in the rug plot below the density plot.

Figure 4 Viral Score values in saliva samples from asymptomatic and symptomatic subjects with the viral infection. P-value of the t-test is provided.