[gpm]

Note that the recent numbers in the CDC chart all seem to be measuring antibodies that only appear from infection, not vaccination (indicated by a circle instead of a square in the chart), while the numbers from the article appear to be measuring antibodies that appear from either infection or vaccination, so they are not directly comparable.

[Animats]

Yes. Which is annoying. Both can be measured, but apparently the commercial lab data only runs one of the two antibody tests.

There's also a blood bank antibody test. That's useful as a crosscheck. People who have blood drawn for medical purposes are in general sicker than average, and those who donate blood are healthier than average. So those set bounds on the measured values.