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How Sample Types Affect COVID-19 Rapid Test Results

May 22, 2020

Finger prick COVID-19 rapid tests have recently been making their rounds in the market and are gaining a lot of interest. Whether it be through the news or shared online videos, we can see both experts and non-experts conducting antibody tests through finger pricking (as shown in the video compilation below).

And it’s easy to see the attraction. All you’ll need to do is to prick the finger with a retractable needle, drop blood and some diluent on a strip, then wait a few minutes for the colored stripe to appear.

Finger pricking for antibody tests may have convenience on its side. Reliability, however, is definitely not.

KEY POINTS
• Blood from finger prick tests do not have enough antibodies to yield reliable results.
• The Innovita rapid test kits must be administered according to the procedure specified by the manufacturer. Any slight deviation from the procedure may cause a high probability of error.
• Tests conducted by non-medical professionals might yield invalid results due to possible mishandling of equipment and samples.

Finger prick tests are problematic.

Steve Miller, the director of the University of California’s clinical microbiology lab warned that the samples gained from finger pricking can be unreliable. He cautioned that these tests tap into shallow capillaries which have little to no serum (the part of the blood that has antibodies). The antibodies are more present in the blood drawn from a vein at a volume which can only be retrieved by medical professionals. Finger pricking also increases the risk of contamination since the possibly infected capillary blood is exposed. Then, there is the tendency of insufficient blood sample when the capillary blood is simply dropped directly onto the test card.

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What It Takes to Run the Innovita COVID-19 Antibody Test

In using the Innovita COVID-19 rapid test kit, the set process indicated in its package insert must be followed. Retrieving samples via finger prick is absolutely discouraged since, as stated before, capillary whole blood contains insufficient antibodies. It is best to abide by the procedure recommended by the manufacturer for ensured accuracy and reliability.

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With the highest antibody concentration, serum is the ideal sample type to use. To retrieve this sample type, certain specialized equipment such as a centrifuge are required. These sample types also need to be processed from the extracted venous blood which necessitates the skills of a trained medical professional.

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The bottom line is that antibody testing is a rigorous and detailed process that cannot and should not be simplified by the finger prick method. For a country already short of testing supplies, wasting kits through incorrect testing procedure is both reckless and irresponsible.

As a distributor of these essential test kits, the company hopes that our healthcare professionals would conduct their testings more carefully. One of the most reliable weapons we have against this crisis should not be compromised by misinformation. Spread the word and say no to finger prick COVID-19 rapid tests.

MEDTEK has partnered with several medical institutions to launch our mobile lab. Through this project, we hope to assist companies in having their returning employees screened for COVID-19. We will bring a team of certified professionals, along with all the necessary test kits and equipment, and have their employees tested right on-site. If you’re interested in availing this service, please fill out the form below.

Sources:
Are we ready for at-home Covid-19 antibody tests? – Quartz
What is Serum? – Sciencing
Government concedes coronavirus finger-prick tests ‘of limited use’ in diagnosing COVID-19 – ABC News
The FDA Tightens the Rules for Covid-19 Antibody Blood Tests – Wired

Author

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Isabela Castañeda

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