Can you please explain why all tests for ovulation are done on day 22

Can you please explain why all tests for ovulation are done on day 22(ie 8 long days after ovulation)?I mean why not day of ovulation or 1-2days post ovulation?

All tests for ovulation r actually tests of progesterone (which is from corpus luteum…which is formed only if ovulation has occured)

Max levels of progesterone occurs on day 22 , hence all tests for ovulation is done on day 22 to get accurate results.

Mind it LH based detection kits to predict ovulation is not done on day 22