How It Works

HomeCOVID-19 Test KitsHow It Works

Test Principle

The One Step SARS-CoV2(COVID-19)IgG/IgM (Whole Blood/Serum/Plasma) is a lateral flow immunochromatographic assay. The test uses anti-human lgM antibody (test line IgM), anti-human lgG(test line lgG and goat anti-rabbit igG (control line C) immobilized on a nitrocellulose strip. The burgundy colored conjugate pad contains colloidal gold conjugated to recombinant COVID-19 antigens conjugated with colloid gold (COVID-19 conjugates and rabbit lgG-gold conjugates. When a specimen followed by assay buffer is added to the sample well, IgM &/or lgG antibodies if present, will bind to COVID-19 conjugates making antigen antibodies complex. This complex migrates through nitrocellulose membrane by capillary action. When the complex meets the line of the corresponding immobilized antibody (anti-human IgM &/or anit-human lgG) the complex is trapped forming a burgundy colored band which confirm a reactive test result. Absence of colored band in the test region indicates a non-reactive test result.
The test contains an internal control (C band) which should exhibit a burgundy colored band of the immunocomplex goat anti rabbit IgG/rabbit lgG-gold conjugate regardless of the color development on any of the test bands. Otherwise, the test result is invalid, and the specimen must be retested with another device.

Test Procedure

The SARS-CoV2(COVID-19)IgG/IgM Test can be performed used on Whole Blood /Serum / Plasma.

To collect Fingerstick Whole Blood Specimens:

Interpretation of Results

POSITIVE: Control line and at least one test line appear on the membrane. The appearance of T2 test line indicates the presence of COVID-19 specific IgG antibodies. The appearance of T1 test line indicates the presence of COVID-19 specific IgM antibodies. And if both T1 and T2 line appear, it indicates that the presence of both COVID-19 specific IgG and IgM antibodies. The lower the antibody concentration is, the weaker the result line is.

*NOTE: The intensity of the color in the test line regions may vary depending on the concentration of SARS-CoV-2 antibodies present in the specimen. Therefore, any shade of color in the test line region should be considered positive.

NEGATIVE: One colored line appears in the control region(C).No apparent colored line appear in the test line region.

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 with a new test device. If the problem persists, discontinue using the test kit immediately and contact your local distributor.

QUALITY CONTROL: A colored line appearing in the control region (C) is an internal procedural control. It confirms sufficient specimen volume and correct procedural technique.

Storage and Stability

– Store as packaged℃ in the sealed℉ pouch at room temperature or refrigerated (4-30 or 40-86 ). The test device is stable through the expiration date printed on the sealed pouch.

– The test must remain in the sealed pouch until use.


– Test cassette is stable for 12 months from the date of production when stored properly in unopened aluminum foil pouches with desiccant.


As with all diagnostic tests, all results must be considered with other clinical information available to the physician. If the test result is negative and clinical symptoms persist, additional follow-up testing using other clinical methods is suggested. A negative result at any time does not preclude the possibility of SARS-CoV-2 infection.

Make An Appointment