Diagnostic Accuracy of 2 cm Versus 4 cm Insertion Depth for Nasal Swabs for SARS-CoV-2 (COVID-19) Rapid Antigen Testing-A Randomized Controlled Trial

Rigshospitalet, Denmark317 enrolled

Overview

This study aims to compare the diagnostic accuracy of rapid antigen detection tests (RDTs) for SARS-CoV-2 using nasal swab insertion depths of 2 cm versus 4 cm. The study is an investigator-initiated, randomized clinical trial conducted at a public COVID-19 test center in Copenhagen, Denmark. Following enrollment, participants complete a questionnaire regarding symptoms and vaccination status. Participants are randomized in a 1:1 ratio to one of two sampling sequences: either a 2 cm swab in the left nostril and a 4 cm swab in the right nostril, or vice versa. All participants undergo a healthcare worker-collected throat swab for RT-PCR analysis, which serves as the reference standard for SARS-CoV-2 infection.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

317

Conditions

COVID -19

Interventions

Eligibility

Sex: ALLMin age: 16 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Citizens, aged 16 years or older, showing up for a SARS-CoV-2 RT-PCR test at Testcenter Valby in Copenhagen, Denmark Exclusion Criteria: * non-fluent in Danish * citizens with nasopharyngeal or oropharyngeal anomalies (e.g. neck breathers with tracheostomy)

Outcomes

Primary Outcomes

Diagnostic accuracy (sensitivity and specificity) of SARS-CoV-2 antigen rapid diagnostic tests (Ag-RDTs) using nasal swabs collected at 2 cm versus 4 cm insertion depth, with RT-PCR as the reference standard

Time frame: Baseline (during the study visit at the time of sample collection). Ag-RDT results were available immediately, whereas RT-PCR results were reported the following days (1-3 days).

Secondary Outcomes

Test discomfort on a 10-point VAS-scale

Test discomfort was evaluated using a 10-point visual analogue scale (VAS), ranging from 0 (no discomfort) to 10 (worst imaginable discomfort).

Time frame: Baseline (during the study visit at the time of sample collection).

Self-reported symptoms of disease

Self-reported symptoms of SARS-CoV-2 infection collected via questionnaire at enrollment, including presence, type, and duration of symptoms (e.g., fever, cough, sore throat, nasal congestion, loss of taste or smell)

Time frame: Baseline (during the study visit at the time of sample collection). Self-reported symptoms of disease were collected immediately prior to testing, during the study visit.