If your child needs to take this pre-test/ post-test for math and reading and you're a little mystified by the results (like I was) and are too curious to wait for your education specialist (or some other administrator) to explain the results to you (like I was), this document might be of help. (Previous link was broken. This link updated Oct 2013)
Other possibly useful links to interpret the Scantron reading test results:
Oral silent reading to Lexile score conversion (accurate conversion for CA 2nd graders?)
What does the Lexile measure mean?
Lexile to grade level conversion