COVID-19 Antigen Test is a lateral flow immunoassay intended for the qualitative detection SARS-CoV-2 nucleocapsid antigens in nasopharyngeal swab and oropharyngeal swab from individuals who are suspected of COVID-19 by their healthcare provider.
Results are for the identification of SARS-CoV-2 nucleocapsid antigen. Antigen is generally detectable in nasopharyngeal swab and oropharyngeal swab during the acute phase of infection. Positive results indicate the presence of viral antigens, but clinical correlation with patient history and other diagnostic information is necessary to determine infection status. Positive results do not rule out bacterial infection or co-infection with other viruses. The agent detected may not be the definite cause of disease.
Negative results do not rule out SARS-CoV-2 infection and should not be used as the sole basis for treatment or patient management decisions, including infection control decisions. Negative results should be considered in the context of a patient’s recent exposures, history and the presence of clinical signs and symptoms consistent with COVID-19, and confirmed with a molecular assay, if necessary for patient management.
COVID-19 Antigen Test is intended for use by trained clinical laboratory personnel specifically instructed and trained in vitro diagnostic procedures.
The novel coronaviruses (SARS-CoV-2) belong to the β genus. COVID-19 is an acute respiratory infectious disease. People are generally susceptible. Currently, the patients infected by the novel coronavirus are the main source of infection; asymptomatic infected people can also be an infectious source.
Based on the current epidemiological investigation, the incubation period is 1 to 14 days, mostly 3 to 7 days. The main manifestations include fever, fatigue and dry cough. Nasal congestion, runny nose, sore throat, myalgia and diarrhea are found in a few cases.
COVID-19 Antigen Test is an immunoassay based on the principle of the double antibody-sandwich technique. COVID-19 Antigen Test is designed to detect nucleocapsid antigen from the SARS-CoV-2 in nasopharyngeal swab and oropharyngeal swab, from patients who are suspected of COVID-19 by their healthcare provider.
During testing, a specimen migrates upward by capillary action. The SARS-CoV-2 antigens if present in the specimen will bind to the antibody conjugates. The immune complex is then captured on the membrane by the pre-coated SARS-Co-2 nuclenocapsid protein monoclonal antibody, and a visible colored line will show up in the test line region indicating a positive result. In the absence of SARS-CoV-2 antigens, a colored line will not form in the test line region indicating a negative result.
To serve as a procedural control, a colored line will always appear at the control line region, indicating that proper volume of specimen has been added and membrane wicking has occurred.
The test cassette contains a membrane strip coated with anti-SARS-CoV-2 nuclenocapsid protein monoclonal antibody on the T test line, and a dye pad which contains colloidal gold coupled with SARS-CoV-2 nuclenocapsid protein monoclonal antibody.
The quantity of tests was printed on the labeling.
Materials Required But Not Provided
Specimens obtained early during symptom onset will contain the highest viral titers; specimens obtained after five days of symptoms are more likely to produce negative results when compared to an RT-PCR assay. Inadequate specimen collection, improper specimen handling and/or transport may yield a falsely negative result; therefore, training in specimen collection is highly recommended due to the importance of specimen quality for generating accurate test results.
Insert minitip swab with a flexible shaft (wire or plastic) through the nostril parallel to the palate (not upwards) until resistance is encountered or the distance is equivalent to that from the ear to the nostril of the patient, indicating contact with the nasopharynx. Swab should reach depth equal to distance from nostrils to outer opening of the ear. Gently rub and roll the swab. Leave swab in place for several seconds to absorb secretions. Slowly remove swab while rotating it. Specimens can be collected from both sides using the same swab, but it is not necessary to collect specimens from both sides if the minitip is saturated with fluid from the first collection. If a deviated septum or blockage creates difficulty in obtaining the specimen from one nostril, use the same swab to obtain the specimen from the other nostril.
Oropharyngeal Swab Sample
Insert swab into the posterior pharynx and tonsillar areas. Rub swab over both tonsillar pillars and posterior oropharynx and avoid touching the tongue, teeth, and gums.
After Swab specimens were collected, swab can be stored in extraction reagent provided with the kit. Also, can be stored by immersing the swab head in a tube containing 2 to 3 mL of virus preservation solution (or isotonic saline solution, tissue culture solution, or phosphate buffer).
Sample Transport and Storage
Freshly collected specimens should be processed as soon as possible, but no later than one hour after specimen collection. Specimen collected may be stored at 2-8℃ for no more than 24 hours; Store at -70 ℃ for a long time, but avoid repeated freeze-thaw cycles.
Allow the test device and specimens to equilibrate to temperature (15-30℃ or 59-86℉) prior to testing.
Positive:*Two lines appear. One colored line should be in the control region (C), and another apparent colored line adjacent should be in the test region (T). Positive for the presence of SARS-CoV-2 nucleocapsid antigen. Positive results indicate the presence of viral antigens but clinical correlation with patient history and other diagnostic information is necessary to determine infection status Positive results do not rule out bacterial infection or co-infection with other viruses. The agent detected may not be the definite cause of disease.
Negative: One colored line appears in the control region (C). No line appears in the test region (T). Negative results are presumptive. Negative test results do not preclude infection and should not be used as the sole basis for treatment or other patient management decisions, including infection control decisions, particularly in the presence of clinical signs and symptoms consistent with COVID-19, or in those who have been in contact with the virus. It is recommended that these results be confirmed by a molecular testing method, if necessary, for patient management.
Invalid: Control line fails to appear. Insufficient specimen volume or incorrect procedural techniques are the most likely reasons for control line failure. Review the procedure and repeat the test using a new test cassette. If the problem persists, discontinue using the lot immediately and contact your local distributor.
A procedural control is included in the test. A colored line appearing in the control region (C) is considered an internal procedural control. It confirms sufficient specimen volume, adequate membrane wicking and correct procedural technique.
Control standards are not supplied with this kit. However, it is recommended that positive and negative controls be tested as good laboratory practice to confirm the test procedure and to verify proper test performance.
Limit of Detection (Analytical sensitivity)
The Limit of Detection (LoD) of the COVID-19 Antigen Test is 5×102.67 TCID50/mL (cultured SARS-CoV-2 virus).
Cross Reactivity (Analytical specificity)
Cross reactivity with following Virus or Bacteria culture with certain concentration has been studied. The results were found negative when tested with the COVID-19 Antigen Rapid Test:
|Influenza A (H1N1)||1×10^6 PFU/mL||-|
|Influenza A (H3N2)||1×10^6 PFU/mL||-|
|Influenza B (Yamagata)||1×10^6 PFU/mL||-|
|Influenza B (Victoria)||1×10^6 PFU/mL||-|
|Human metapneumovirus||1×10^6 PFU/mL||-|
|Parainfluenza virus||1×10^6 PFU/mL||-|
|Respiratory syncytial virus||1×10^6 PFU/mL||-|
|Streptococcus pyogenes||1×10^7 PFU/mL||-|
|Candida albicans||1×10^7 PFU/mL||-|
|Mycoplasma pneumoniae||1×10^7 PFU/mL||-|
|Chlamydia pneumoniae||1×10^7 PFU/mL||-|
|Legionella pneumophila||1×10^7 PFU/mL||-|
|Human coronavirus 229E||1×10^6 PFU/mL||-|
|Human coronavirus OC43||1×10^6 PFU/mL||-|
|Human coronavirus NL63||1×10^6 PFU/mL||-|
|Human coronavirus HKU1||1×10^6 PFU/mL||-|
To estimate the clinical performance between COVID-19 Antigen Test Cassette and the PCR comparator, 162 nasopharyngeal swab were collected from patients who were suspected of COVID-19.
Summary data of COVID-19 Antigen Rapid Test by nasopharyngeal swab as below:
Positive Percent Agreement (PPA)=84.38% (27/32), (95%CI: 68.25%～93.14%)
Negative Percent Agreement (NPA) =100% (130/130), (95%CI: 97.13%～100%)