SG Diagnostics

SG Diagnostics COVID-19 Antigen Rapid Test Kit (Professional Use)

The SG Diagnostics COVID-19 Antigen Rapid Test Kit (Colloidal Gold-Based) is a lateral flow immunoassay intended for the qualitative detection of nucleocapsid protein antigen from SARS-CoV-2 in direct swabs from individuals suspected of COVID-19 by their healthcare provider.

The novel coronavirus SARS-COV-2 is the causative pathogen for the global pandemic of COVID-19 that has spread to 219 countries. Most infected people will experience mild to severe respiratory illness and recover without special treatment. The most common symptoms are fever, cough and fatigue. Older people and those with underlying medical problems (e.g. cardiovascular disease, diabetes, chronic respiratory disease and cancer) are more likely to develop serious illness and serious symptoms include difficulty breathing or shortness of breath, chest pain and loss of speech or movement. It typically takes 5 – 6 days for someone that is infected with the virus for symptoms to appear but it can take up to 14 days in some individuals.

Source: economist.com


The SG Diagnostics COVID-19 Antigen Rapid Test Kit is an immunochromatographic membrane assay that uses highly sensitive antibodies to detect SARS-CoV-2 spike and nucleocapsid protein antigens from swab samples via the double antibody sandwich method. After loading, the sample will diffuse upwards from the charging end by capillary action, and then the SARS-CoV-2 spike and nucleocapsid protein antigens in the sample will combine with the antibody in the marker pad to form colloidal gold antibody-antigen complex; the complex continues to diffuse upwards to the nitrocellulose membrane with the sample, and then blocked by Test (T) Line packed with antibody to form colloidal gold labeled antibody-antigen-immune complex. The rest unblocked colloidal gold complex continues to move upwards and combine with the Control (C) line (quality control line), indicating that the reaction is completed.

  • The assay time is shorter (within 10 minutes as compared to around 24 hours for enzyme-linked immunosorbent assay (ELISA))
  • The cost is cheaper than ELISA
  • The test can be carried out at the point-of-care
  • It is a one-step assay that requires no special skills or instrumentation to achieve the result(s)
  • It has a long shelf life and assay reagents do not require refrigeration or freezer storage



Specimen Collection

  • Nasal Swab Specimen (Recommended)

Insert the sterile swab into one nostril. The swab tip should be inserted up to 2.5 cm (1 inch) from the edge of the nostril. Roll the swab 5 times along the mucosa inside the nostril to ensure that both mucus and cells are collected. Repeat this process for the other nostril to ensure that an adequate specimen is collected from both nasal cavities (use the same swab).

  • Oropharyngeal Swab Specimen (Optional)

Insert the sterile swab into the throat that presents the most secretion from the red area of the throat wall and maxillary tonsils to collect throat swab specimens. Rub the bilateral throat tonsils and throat wall moderately to obtain the specimen. Please do not touch the tongue when removing the swab.

  • Nasopharyngeal Swab Specimen (Optional)

Insert the sterile swab into the nostril that presents the most secretion under visual inspection. Keep the swab near the septum floor of the nose while gently pushing the swab into the posterior nasopharynx. Rotate the swab 5 times then remove it from the nasopharynx.

For all of the specimen collection methods, it is important to obtain as much secretion as possible. Freshly collected specimens should be tested as soon as possible.

Note: The test cassette must be at room temperature before use, and the test must be operated at room temperature.


  1. Place and soak the Patient Swab in the Sample Eluent for 10 seconds and then stir well by rotating the swab against the side of the vial 5 times.
  2. Remove the Patient Swab while squeezing the middle of the Sample Eluent Vial to remove the liquid from the swab. Discard the swab in biohazard waste.
  3. Firmly attach Dropper Lid to the top of the Sample Eluent Vial.
  4. Gently invert the Sample Eluent Vial five times just before applying the sample to the Test Cassette.
  5. Apply the extracted sample from the Sample Eluent Vial onto the charging hole of the Test Cassette. To do this, gently press the sides of the Sample Eluent Vial to add 4 drops (about 80μL) of extracted sample to the charging hole of the Test Cassette. The sample will then be drawn by capillary action into the Test Strip.
  6. Start and timer and read the results after 10 minutes. The result is invalid after 15 minutes.
  7. Dispose the Swab, Sample Eluent Vial and Test Cassette in the appropriate biohazard waste.

Note: In a valid, tested device, a red line appears at the Control Line position, confirming that the sample has flowed through the test strip and the reagents are working.


The test results are analyzed as follows:

A negative specimen will give a single red colored Control Line in the top half of the window, indicating a negative result. This Control Line means that the detection part of the test was done correctly, but no COVID-19 antigen was detected.

A positive specimen will give two red colored lines. This means that COVID-19 antigen was detected. Specimens with low levels of antigen may give a faint sample Line. Any visible red colored Sample Line is positive.

If no lines are seen, if just the red Test Line is seen, or if the red Control Line is not seen, the assay is invalid. Invalid tests should be repeated.

Coming soon

CE, Singapore (HSA), Philippines (FDA), Germany (Bfarm), Italy, Columbia (INVIMA) , Peru, UAE, Hungary

Test Kit Specifications Materials Provided

Parameter Specification
Test Cassettes (20)
A test cassette consists of test strip, packed individually in a sealed desiccant foil pouch.
Disposable Swab (20)
Sterile swabs for use with test Cassette
Sample Eluent (1)
0.5mL of phosphate buffer with surfactant
Product Insert (1)

Test Kit Characteristics

Parameter Specification
Assay format
Lateral flow test / immunochromatographic
Testing Time
10 – 15 mins
99.29% (95%Cl: 98.54%-99.66%)
97.57% (95%Cl: 94.45 %-98.96%)
Type of analyte
Spike protein antigen and Nucleocapsid protein antigen
Sample material
Nasal, Oropharyngeal or Nasopharyngeal Swab Specimen

External Clinical Evaluation


For more information, you can download the file below.

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