SARS-CoV InfectionDETACNCT04745533
COVID-19 Contact Study by Antigen Detection Test
An observational study of SARS-CoV Infection, run by Juan Fernando Masa Jiménez.
Trial summary
Stopping the SARS-CoV2 spread is essential to control the pandemic cause by this virus. A great effort is being made to carry out surveillance, case detection and contact control protocols in order to detect and isolate those contagious subjects. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- SARS-CoV Infection
- What is being tested?
- Antigen detection test
- How many people
- 0 participants
- Where
- No sites listed yet
- Study dates
- 15 Feb 2021to 30 Jun 2021
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: All subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health of Spain in the health area of Cáceres
Who may be able to join
- Subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health of Spain at the time of inclusion.
Who cannot join
- Subjects who do not obtain their informed consent for the study.
- Symptomatic subject at the time of inclusion.
About this study
Official title: Diagnostic Efficacy of the SARS-CoV2 Antigen Detection Test for the COVID-19 Contact Study
Stopping the SARS-CoV2 spread is essential to control the pandemic cause by this virus.
A great effort is being made to carry out surveillance, case detection and contact control protocols in order to detect and isolate those contagious subjects.
Read more
Since both symptomatic and asymptomatic subjects can be contagious, a surveillance system based on the presence of symptoms is not enough, requiring to perform diagnostic tests in a large number of subjects, such as asymptomatic contacts or high-prevalence populations, and repeatedly. Moreover, the speed in obtaining results is crucial in order not to delay the isolations of positive subjects.
The polymerase chain reaction (PCR) is an expensive test which requires specialized equipment and personnel with a delay in results of 24-48 hours. In addition, its high sensitivity can mean that subjects without infective capacity have a positive result.
In contrast, antigen detection tests (ADTs) are cheap and easy to perform, having a result in few minutes. They have shown high sensitivity and specificity in symptomatic subjects, specially in the first week of symptoms when the viral load is high. This could be very useful for the study of asymptomatic contacts to detect those with potential contagiousness quick, easily and cheaply. However, there is no evidence to support the use of ADTs in this group of subjects.
For this reason, the investigators propose to carry out a study to compare the diagnostic efficacy of ADTs versus PCR in the group of subjects considered to be close contacts of SARS-Cov2 positive patients in the health area of Cáceres.
- Conditions
- SARS-CoV Infection
- Being tested
- Antigen detection test
- Keywords
- Antigen detection tests, Diagnostic efficacy, Contact study, Asymptomatic contacts
- Medical subject headings
- Severe Acute Respiratory Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Antigen detection testDiagnostic test
To compare the results of the antigen detection test against the polymerase chain reaction in the study of contacts of COVID-19 patients during quarantine.
| Study group | Role | What they receive |
|---|---|---|
| SARS-CoV2 contacts | Subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health in the health area of Cáceres. Receives: Diagnostic Test: Antigen detection test |
What is being measured
The primary outcome is the main question the study is designed to answer.
Sensitivity of the antigen detection test used in the study of contacts of COVID-19 patients.
The investigators will analyze the probability of a positive antigen detection test result in a COVID-19 patient contact with a positive polymerase chain reaction test.
Measured: 2 days
Specificity of the antigen detection test used in the study of contacts of COVID-19 patients.
The investigators will analyze the probability of a negative antigen detection test result in a COVID-19 patient contact with a negative polymerase chain reaction test.
Measured: 2 days
Secondary outcomes (10)
Positive predictive value of the antigen detection test used in the study of contacts of COVID-19 patients.
The investigators will analyze the probability that a subject considered COVID-19 patient contact with a positive antigen detection test result has a positive polymerase chain reaction test.
Measured: 2 days
Negative predictive value of the antigen detection test used in the study of contacts of COVID-19 patients.
The investigators will analyze the probability that a subject considered COVID-19 patient contact with a negative antigen detection test result has a negative polymerase chain reaction test.
Measured: 2 days
Positive likelihood ratio of the antigen detection test used in the study of contacts of COVID-19 patients.
The investigators will analyze how much the probability of having a positive polymerase chain reaction test increases when a subject considered a COVID-19 patient contact has a positive antigen detection test.
Measured: 2 days
Negative likelihood ratio of the antigen detection test used in the study of contacts of COVID-19 patients.
The investigators will analyze how much the probability of having a positive polymerase chain reaction test decreases when a subject considered a COVID-19 patient contact has a negative antigen detection test.
Measured: 2 days
Change in the pretest probability when the antigen detection test result is positive in a COVID-19 patient contact.
The investigators will analyze the change that occurs in the probability that a subject considered a COVID-19 contact has a positive polymerase chain reaction test before and after performing an antigen detection test with a positive result
Measured: 2 days
Change in the pretest probability when the antigen detection test result is negative in a COVID-19 patient contact.
The investigators will analyze the change that occurs in the probability that a subject considered a COVID-19 contact has a positive polymerase chain reaction test before and after performing an antigen detection test with a negative result
Measured: 2 days
Cut-off point of the cycle threshold of the polymerase chain reaction test that discriminates infectivity.
The investigators will analyze the cut-off point of polymerase chain reaction test (PCR) cycle threshold that maximizes discrimination of patients with at least one close contact with positive PCR (infectivity in the first circle of contacts).
Measured: 2 weeks
Risk of SARS-CoV2 infection in close contacts of COVID-19 patients with a positive polymerase chain reaction test depending on whether the antigen detection test is positive or negative.
The investigators will compare the number of infected subjects by COVID-19 patient contacts with a positive polymerase chain reaction test, depending on whether the antigen detection test is positive or negative
Measured: 2 weeks
To predict a positive result of the polymerase chain reaction test based on the appearance of symptoms during quarantine
Researchers will analyze the appearance of symptoms during quarantine in the contacts of COVID-19 patients and whether or not they have a positive polymerase chain reaction test.
Measured: 10 days
The percentage of COVID-19 patient contacts with symptoms during the quarantine.
The investigators analyze the percentage of contacts of COVID-19 patients who develop symptoms during the quarantine.
Measured: 10 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Feb 2021
- Study start15 Feb 2021
- Primary completion30 Apr 2021
- Study completion30 Jun 2021
Why it stopped: Lack of financing. Furthermore, antigen tests were incorporated into contact detection, so the study lost interest.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for SARS-CoV InfectionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Juan Fernando Masa Jiménez
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Juan Fernando Masa Jiménez, University of Extremadura
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04745533
- Sponsor's protocol ID
- 12/2020
- Acronym
- DETAC
- Status last verified
- Apr 2026
- First submitted
- 4 Feb 2021
- Last updated
- 29 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Additional related documents such as study protocol, statistical analysis plan and informed consent form will be available upon request from the project principal investigator. (Dr. Juan Fernando Masa Jiménez). De-identified patients´data can be requested by researchers for use in independent scientific research and will provided following review and approval of the research proposal (including statistical analysis plan) and completion of a data sharing agreement with the Project Publications Committee. Investigator Data requests can be made anytime from 1 to 2 years after the publication of this trial. Requests should be sent to the corresponding author (Dr. Juan Fernando Masa Jiménez- fmasa@separ.es)
Study at a glance
From the registry record, last updated by the sponsor on 29 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Diagnostic Efficacy of the SARS-CoV2 Antigen Detection Test for the COVID-19 Contact Study
- ClinicalTrials.gov ID
- NCT04745533
- Acronym / sponsor ID
- DETAC / 12/2020
- Conditions
- SARS-CoV Infection
- Keywords
- Antigen detection tests, Diagnostic efficacy, Contact study, Asymptomatic contacts
- Study type
- Observational
- Recruitment status
- WithdrawnReason stopped: Lack of financing. Furthermore, antigen tests were incorporated into contact detection, so the study lost interest.
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Juan Fernando Masa JiménezUniversity, hospital or other
- Study start
- 15 Feb 2021 (actual)
- Primary completion
- 30 Apr 2021 (actual)
- Study completion
- 30 Jun 2021 (actual)
- First posted
- 9 Feb 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Stopping the SARS-CoV2 spread is essential to control the pandemic cause by this virus.
A great effort is being made to carry out surveillance, case detection and contact control protocols in order to detect and isolate those contagious subjects.
Since both symptomatic and asymptomatic subjects can be contagious, a surveillance system based on the presence of symptoms is not enough, requiring to perform diagnostic tests in a large number of subjects, such as asymptomatic contacts or high-prevalence populations, and repeatedly. Moreover, the speed in obtaining results is crucial in order not to delay the isolations of positive subjects.
The polymerase chain reaction (PCR) is an expensive test which requires specialized equipment and personnel with a delay in results of 24-48 hours. In addition, its high sensitivity can mean that subjects without infective capacity have a positive result.
In contrast, antigen detection tests (ADTs) are cheap and easy to perform, having a result in few minutes. They have shown high sensitivity and specificity in symptomatic subjects, specially in the first week of symptoms when the viral load is high. This could be very useful for the study of asymptomatic contacts to detect those with potential contagiousness quick, easily and cheaply. However, there is no evidence to support the use of ADTs in this group of subjects.
For this reason, the investigators propose to carry out a study to compare the diagnostic efficacy of ADTs versus PCR in the group of subjects considered to be close contacts of SARS-Cov2 positive patients in the health area of Cáceres.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| SARS-CoV2 contacts | – | Diagnostic Test: Antigen detection testSubjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health in the health area of Cáceres. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- All subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health of Spain in the health area of Cáceres
Key inclusion criteria (1 listed)
- Subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health of Spain at the time of inclusion.
Key exclusion criteria (2 listed)
- Subjects who do not obtain their informed consent for the study.
- Symptomatic subject at the time of inclusion.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Antigen detection testTo compare the results of the antigen detection test against the polymerase chain reaction in the study of contacts of COVID-19 patients during quarantine. | Diagnostic test | SARS-CoV2 contacts |
Primary outcome
Sensitivity of the antigen detection test used in the study of contacts of COVID-19 patients.
Time frame: 2 days
The investigators will analyze the probability of a positive antigen detection test result in a COVID-19 patient contact with a positive polymerase chain reaction test.
Specificity of the antigen detection test used in the study of contacts of COVID-19 patients.
Time frame: 2 days
The investigators will analyze the probability of a negative antigen detection test result in a COVID-19 patient contact with a negative polymerase chain reaction test.
10 secondary outcomes
Positive predictive value of the antigen detection test used in the study of contacts of COVID-19 patients.
Time frame: 2 days
Negative predictive value of the antigen detection test used in the study of contacts of COVID-19 patients.
Time frame: 2 days
Positive likelihood ratio of the antigen detection test used in the study of contacts of COVID-19 patients.
Time frame: 2 days
Negative likelihood ratio of the antigen detection test used in the study of contacts of COVID-19 patients.
Time frame: 2 days
Change in the pretest probability when the antigen detection test result is positive in a COVID-19 patient contact.
Time frame: 2 days
Change in the pretest probability when the antigen detection test result is negative in a COVID-19 patient contact.
Time frame: 2 days
Cut-off point of the cycle threshold of the polymerase chain reaction test that discriminates infectivity.
Time frame: 2 weeks
Risk of SARS-CoV2 infection in close contacts of COVID-19 patients with a positive polymerase chain reaction test depending on whether the antigen detection test is positive or negative.
Time frame: 2 weeks
To predict a positive result of the polymerase chain reaction test based on the appearance of symptoms during quarantine
Time frame: 10 days
The percentage of COVID-19 patient contacts with symptoms during the quarantine.
Time frame: 10 days
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Apr 2026.
- Individual participant dataSharing planned: Yes. Additional related documents such as study protocol, statistical analysis plan and informed consent form will be available upon request from the project principal investigator. (Dr. Juan Fernando Masa Jiménez). De-identified patients´data can be requested by researchers for use in independent scientific research and will provided following review and approval of the research proposal (including statistical analysis plan) and completion of a data sharing agreement with the Project Publications Committee. Investigator Data requests can be made anytime from 1 to 2 years after the publication of this trial. Requests should be sent to the corresponding author (Dr. Juan Fernando Masa Jiménez- fmasa@separ.es)
Related trials for SARS-CoV Infection
Not yet recruiting
Effect of MxA Guidance on Antiviral Treatment in Respiratory Viral Infections
Respiratory Viral Infections, Influenza
Recruiting
Effectiveness of Transcranial Direct Current in Patients With Persistent COVID-19 With Headaches and Chronic Pain.
COVID-19, Long COVID
Active, not recruiting
SARS-COV-2 Seroprevalence and Seroconversion Among Employees of the Universitair Ziekenhuis Brussel Following mRNA COVID-19 Vaccination
SARS-CoV Infection
Active, not recruiting
Clinical Validation of the NowFuture Digital Flu / COVID Test in Anterior Nasal Samples for Over-the-Counter (OTC) Use in Australia
SARS CoV 2 Infection, Influenza A Virus Infection
RecruitingObservational study
Determinants of SARS (Severe Acute Respiratory Syndrome)-COV2 (COVID-19) Persistence After Convalescence
COVID-19, Corona Virus Infection
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of SARS-CoV Infection, run by Juan Fernando Masa Jiménez.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 29 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Sensitivity of the antigen detection test used in the study of contacts of COVID-19 patients. (time frame: 2 days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Apr 2026.