Sensitivity and Specificity of Rapid SARS-CoV-2 Antigen Detection Using Different Sampling Methods: A Clinical...

Area of Science:

• Virology
• Immunology
• Diagnostic Medicine

Background:

• Rapid antigen detection tests for SARS-CoV-2 are prevalent but lack standardized sampling protocols.
• Optimal sample collection is crucial for accurate and reliable viral detection.

Purpose of the Study:

• To evaluate the agreement between SARS-CoV-2 fluorescent antigen detection and real-time reverse-transcriptase polymerase chain reaction (rRT-PCR).
• To compare the sensitivity and reliability of different swab methods for SARS-CoV-2 antigen testing.

Main Methods:

• SARS-CoV-2 detection was performed using an immunofluorescent Quidel system on samples from oropharyngeal (O), nasal (N), and saliva (S) swabs.
• A cohort of 50 COVID-19 positive and 26 healthy patients, confirmed by rRT-PCR, were included.
• Sensitivity and Kappa values were calculated for individual and combined swab methods.

Main Results:

• The combined O/N/S swab method demonstrated the highest sensitivity (86%, Kappa = 0.8).
• Nasal swabs showed 76% sensitivity (Kappa = 0.68), while saliva swabs had the lowest sensitivity (66%, Kappa = 0.57).
• Excellent agreement with rRT-PCR was observed when considering positive detection from any of the O, N, or S samples (Kappa = 0.91 and 0.97).

Conclusions:

• Immunofluorescent antigen detection is a reliable method for rapid SARS-CoV-2 diagnosis.
• Analyzing at least nasal and oropharyngeal swabs enhances diagnostic accuracy.
• A single combined O/N/S swab significantly improves sensitivity compared to individual site sampling.