NCT07597889

Brief Summary

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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
317

participants targeted

Target at P75+ for not_applicable

Timeline
Completed

Started Feb 2023

Shorter than P25 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

February 1, 2023

Completed
25 days until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 26, 2023

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

February 26, 2023

Completed
3.2 years until next milestone

First Submitted

Initial submission to the registry

April 29, 2026

Completed
20 days until next milestone

First Posted

Study publicly available on registry

May 19, 2026

Completed
Last Updated

May 19, 2026

Status Verified

May 1, 2026

Enrollment Period

25 days

First QC Date

April 29, 2026

Last Update Submit

May 18, 2026

Conditions

COVID -19

Keywords

covid-19

Outcome Measures

Primary Outcomes (1)

  • 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

    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 (2)

  • Test discomfort on a 10-point VAS-scale

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

  • Self-reported symptoms of disease

    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.

Study Arms (2)

2 cm nasal swab in the right nostril, and 4 cm nasal swab in the left nostril

EXPERIMENTAL
Diagnostic Test: 4 cm nasal swab - left nostrilDiagnostic Test: 2 cm nasal swab - right nostril

4 cm nasal swab in the right nostril, and 2 cm nasal swab in the left nostril

EXPERIMENTAL
Diagnostic Test: 2 cm nasal swab in the left nostrilDiagnostic Test: 4 cm nasal swab - right nostril

Interventions

4 cm nasal swab - left nostrilDIAGNOSTIC_TEST

a 4 cm nasal swab insertion in the left nostril

2 cm nasal swab in the right nostril, and 4 cm nasal swab in the left nostril
2 cm nasal swab in the left nostrilDIAGNOSTIC_TEST

a 2 cm nasal swab insertion in the left nostril

4 cm nasal swab in the right nostril, and 2 cm nasal swab in the left nostril
4 cm nasal swab - right nostrilDIAGNOSTIC_TEST

a 4 cm nasal swab insertion in the right nostril

4 cm nasal swab in the right nostril, and 2 cm nasal swab in the left nostril
2 cm nasal swab - right nostrilDIAGNOSTIC_TEST

a 2 cm nasal swab insertion in the right nostril

2 cm nasal swab in the right nostril, and 4 cm nasal swab in the left nostril

Eligibility Criteria

Age16 Years+
Sexall
Healthy VolunteersYes
Age GroupsChild (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

  • Citizens, aged 16 years or older, showing up for a SARS-CoV-2 RT-PCR test at Testcenter Valby in Copenhagen, Denmark

You may not qualify if:

  • non-fluent in Danish
  • citizens with nasopharyngeal or oropharyngeal anomalies (e.g. neck breathers with tracheostomy)

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Rigshospitalet

Copenhagen, Denmark

Location

MeSH Terms

Conditions

COVID-19

Condition Hierarchy (Ancestors)

Pneumonia, ViralPneumoniaRespiratory Tract InfectionsInfectionsVirus DiseasesCoronavirus InfectionsCoronaviridae InfectionsNidovirales InfectionsRNA Virus InfectionsLung DiseasesRespiratory Tract Diseases

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
DIAGNOSTIC
Intervention Model
SINGLE GROUP
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
MD, PhD. Principal investigator.

Study Record Dates

First Submitted

April 29, 2026

First Posted

May 19, 2026

Study Start

February 1, 2023

Primary Completion

February 26, 2023

Study Completion

February 26, 2023

Last Updated

May 19, 2026

Record last verified: 2026-05

Data Sharing

IPD Sharing
Will share

Study Protocol

Shared Documents
STUDY PROTOCOL

Locations

DK(1)