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Regarding the COVID-19 Quantitative Spike Protein Antibody test, I know we do not know what level equals immunity, but what is the average immunocompetent person’s level (specifically for Lab Corp’s test in case different labs have different numbers)?

Ask the Doctor Question:

Regarding the COVID-19 Quantitative Spike Protein Antibody test, I know we do not know what level equals immunity, but what is the average immunocompetent person’s level (specifically for Lab Corp’s test in case different labs have different numbers)? Even if it doesn’t “mean anything,” it would be helpful to know how my result as a CLL patient compares to the average immunocompetent person’s level. I know this is currently being studied – are there any articles you can point me to that specify levels as well?

Answer: If the Semi-quant Total Ab number is <0.80, there was no response. If the Semi‑Quantitative Total Ab number is >0.80, there was a response to the vaccine. So unfortunately, there is no information regarding the “average” response just yet or any way to tell what level of protection the huge variation in numbers equates to when it comes to determining level of immunity.

It is important to take into consideration that the maximum value for the Spike antibody response can be upwards of 2,500. While we know that the greater the number equates to more antibodies, at this time we do not fully understand if a lower antibody value equates to a lesser level of protection should you become infected with COVID. It’s true that some immunity is better than no immunity at all, but a low count is unfortunately not ideal.

CLL Society is still urging everyone with CLL, regardless of your vaccine and/or antibody status, to continue wearing a mask in all situations. Preferably a tightly fitted N-95 if possible. Also, please continue to adhere closely to social distancing, and keep up with diligent hand hygiene efforts, especially now that the general population is unmasking after the latest CDC guidelines. We also strongly urge you to have household members vaccinated if possible. We would encourage you to check out Dr. Byrd’s opinion piece that was just posted to our website here:

The true interpretation of the Spike antibody test will become known over time as we learn the association between these results and how it correlates to the chance of still getting infected with COVID in the near future. There are currently many researchers with expertise in blood cancer who are looking at this very subject and performing studies. We should be hearing more about this subject in the coming months.

Stay tuned to CLL Society’s website. If you haven’t already, please consider signing up to receive our weekly newsletters so you can receive the most current information on CLL and COVID-19 as well as recent research updates directly to your inbox.