COVID-19 RAPID TEST KIT

COVID-19 RAPID TEST KIT   

INTRODUCTION:

   RDT is a medical diagnostic test which is used for preliminary examination to detect both early and late markers IgM/IgG antibodies in mankind to avoid spreading of virus by identifying infection rapidly and accurately.  Some define it as qualitative or semi quantitative in-vitro diagnostic test used as a single device.

HISTORY:

 As there is rapid growth in population along with new diseases and new viruses depending only on laboratory test was very hard and found it challenging especially in case of malaria in early 1990’s   where there is huge number of cases were found especially during the climatic changes in environment then they found a solution and rapid diagnostic test came into existence. From then they were for different medical conditions like pregnancy, blood glucose testing which is very friendly to use for every class of people with more accuracy.

In which infections RDT are mostly used:

     There are various infectious conditions these RDT’S are used from the day they started using
Rapid HIV test

Rapid influenza diagnostic test

Malaria antigen detection test

COVID-19 antibody detection test

WORKING PRINCIPLE OF RDT IN COVID:

    COVID-19 RDT is a immunoassay test where the antibodies are embedded into the test strip which binds to covid-19 specific biomarkers IgG AND IgM. When a sample of blood, plasma or serum is added to one end of a strip interacts with the antibodies on strip, leaving a visible test line if patient is infectious. If patient is free from infection no biomarkers are present. There will be separate test lines for IgG, IgM where presence of IgM is an indication of early infection and presence of IgG is a later stage of infection ( usually 7 days or longer).

This tests are used as both primary and secondary diagnosis of COVID -19. After the recovery as a second opinion.

How it works

Collect and pile up blood/serum/plasma sample.

Add blood/serum/plasma sample collected to sample well.

Place 2-3 drops of buffer solution in sample well.

Read results which are visible after 15-30 minutes.

Results

Negative Result: If only the quality control (C) appears and G and M are not visible, then the result is negative.

Positive Result, M only: If both Control and M appear, then the result is positive for the IgM antibody.

Positive Result, G only: If both Control and G appear, then the result is positive for the IgG antibody.

Positive Result, G and M: If Control and both G and M appear, then the result is positive for both the IgG and IgM antibodies.

In addition there are also antigen tests available but are not currently practiced for clinical diagnosis or preliminary diagnosis.

PROS:
Identifies both symptomatic and asymptomatic cases.

Easy to use and read the results with no specialist or equipment needed.

Results are rapid within 10-30 minutes and cost effective over laboratory techniques.

No need of any special storage for kits and screening can be done anywhere.

Accuracy of IgM  , IgG IS 97.8%, 99.6% respectively.

• Sensitivity >91%
• Specificity>99%
• Accuracy >97%

• No other medications are interfered with the test.

CONS:

• It is possible to be exposed to covid-19 but they do not develop antibodies. These type of cases are not possible with other lab techniques.

  

• There may be also some other virus infections where presence of IgG, IgM is found which can be differentiated by other technique like PCR test.

 CONCLUSION:

    Though rapid diagnostic test are used from early 1990’s but recently from last two months everyone started speaking of rapid tests which are giving rapid results to find the COVID positive cases globally, as we don’t have abundant sources of laboratories to conduct test where we have mass number of cases to rule out from the crisis as  these  are  time saving and cost effective but only used as primary diagnosis but not confirmatory diagnostic test. But there are many governments claimed that rapid test for corona is not effective but that variation is only due to window period of virus so there is great usage of raid test kit in COVID-19 crisis

REFERENCES:

  1.      https://www.oxfordbiosystems.com/COVID-19-Rapid-test

  2.      https://www.biomedomics.com/products/infectious-disease/covid-19-rt/

                                                      

                                                                                                                      Blog by

                                                                                                               Mamillapalli.Aruna Lakshmi