My son took the K-Bit in K as a screening instrument to see if he could get further testing for gifted and missed the cut off for more testing by one question. In our district, the screening K-Bit is administered by the guidance counselor and not the psychologist (individually administered so it isn't a group thing). This particular guidance counselor said she really didn't think that it was particularly valid as a screen for K students because most kids who miss by one or two questions in K pass it with room to spare the next year. And my son as a K student was just as much gifted at 5 as he was a year later at 6.
Then he got the K-bit again at the end of 1st grade and did just fine on it, passed the screen and qualified for more testing. He finally got the full testing this year and his full IQ testing was much higher than the K-bit screen score.