[Introduction]

Coronaviruses are enveloped RNA viruses that are distributed broadly among humans, other mammals, and birds and that cause respiratory, enteric, hepatic, and neurologic diseases. Seven coronavirus species are known to cause human disease. Four viruses - 229E, OC43, NL63, and HKU1 - are prevalent and typically cause common cold symptoms in immunocompetent individuals. The three other strains - severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and 2019 Novel Coronavirus (COVID-19) - are zoonotic in origin and have been linked to sometimes fatal illness. IgG and IgM antibodies to 2019 Novel Coronavirus can be detected with 2-3 weeks after exposure. IgG remains positive, but the antibody level drops overtime.

[Principles of the Assay]

DIAKEY COVID 19 IgM/IgG Rapid Test device is a qualitative membrane strip based immunoassay for the detection of antibodies (IgG and IgM) to Novel coronavirus in human Whole Blood/Serum/Plasma. The test device consists of: 1) a burgundy colored conjugate pad containing Novel coronavirus recombinant envelope antigens conjugated with Colloid gold (Novel coronavirus conjugates), 2) a nitrocellulose membrane strip containing two test lines (IgG and IgM lines) and a control line (C line). The IgM line is pre-coated with the Mouse anti-Human IgM antibody, IgG line is coated with Mouse anti-Human IgG antibody. When an adequate volume of test specimen is dispensed into the sample well of the test device, the specimen migrates by capillary anction across the device. IgM anti-Novel coronavirus, if present in the specimen, will bid to the Novel coronavirus conjugates. The immunocomplex is then captured by the reagent pre-coated on the IgM band, forming a burgundy colored IgM line, indicataing a Novel coronavirus IgM positive test result. IgG anti-Novel coronavirus if present in the specimen will bind to the Novel coronavirus conjugates. The immunocomplex is then captured by the reagent coated on the IgG line, forming a burgundy colored IgG line, indicating a Novel coronavirus IgG positive test result. Absence of any T lines (IgG and IgM) suggests 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.

[Storage and Stability]

1. Store as packaged in the sealed pouch at the temperature (4-30°C or 40-86°F). The kit is stable within the expiration date printed on the labeling. 

2. Once open the pouch, the test should be used within one hour. Prolonged exposure to hot and humid environment will cause product deterioration. 

3. The LOT and the expiration date were printed on the labeling.

[Procedure]

● SPECIMEN COLLECTION AND STROAGE

1. Specimen to be tested should be obtained and handled by standard methods for their collections.

2. Serum: Allow the blood to clot, then centrifuge to separate the serum.
3. Plasma: Collect the whole blood into the tube containing anticoagulants such as heparin, citrate, or EDTA. Centrifuge the blood and separate the plasma.

4. Whole blood: whole blood should be collected over heparin, citrate, or EDTA. Mix the blood by inversion and use it to the test. If fingertip blood is used to the test, prick the finger and collect the blood by a capillary tube. And then, load the blood onto the sample well (S) of the test device.

5. All specimens should be tested as soon as early they are prepared, if necessary, they may be stored at 2-8°C for up to 24 hours or at -20°C for longer periods. 

● TEST PROCEDURE

1. Allow the test device and specimens (Whole Blood/Serum/Plasma) to equilibrate to temperature(15-30°C or 59-86°F) prior to testing.

2. Remove the test device from the sealed pouch.
3. Hold the dropper vertically and transfer 1 drop of specimen (approximately 10ul) to the specimen well (S) of the test device, then add 2 drops buffer (approximately 70ul) and start the timer. See the illustration below.

4. Wait for colored lines to appear. Interpret the test results in 10-15 minutes. Do not read results after 20 minutes.