LCPS offers an appeals process, but has anyone asked how often decisions are overturned? The answer is almost never, unless there is compelling additional evidence (such as a full scale IQ score) to reverse it.
Think about it- if they overturned the eligibility decision of even the small sampling of children whose parents have posted on this site, based on eleventh hour input from extracurricular music or art teachers, they would be undermining the validity of their own process.
Unless you have an IQ test score of 130+, I would not advise going through the appeals process in LCPS. Instead, I would consider nominating your child to the screening pool, yourself, next year and going through the process again, using every available question/space/opportunity to show aspects of your child that cannot be measured by ability testing.
Good luck to all.