I have used the Kbit-2 composite IQ for both high and primary school children. there is 3 components that this test covers and yes it is not the best and full testing that i would expect gifted and talented children would endure. it would only be the quick version to decide does your child have those traits. really traits is not true as kbit tests verbal( and non verbal capabilities with a matrices section that i find is excellent for ESL students. I will add another test that i think they made have used prior at the end of this.
section 1: the child looks at 6 pictures (all on one page) and one of those pictures matches the word you say. eg you say ball and the child has to indicate the picture with a ball in it. You show another 6 pictures and say another word and so on. the words are based on a progression that they get harder until the child get 4 wrong in a row then you go back and add all the correct ones. A picture of a ball may come up 3 times through the test and the tester may say globe and then may say sphere as the scoring is based on where the child should be at a certain age. This sort of testing is looking for the child's receptive knowledge so you can imagine that the child would need to get plenty of verbal communication throughout their growth to get a high score.
section 2: riddles. there is about 40 riddles to get through and each one gets harder until the child gets 4 wrong. eg I have a tail and bark? the child has to work out the answer and say dog.
section 3: Matrices. progresses also from easy to hard and the child looks at patterns and has to pick the matching pattern. you might get 9 squares with pictures in it and one picture is missing. you get 6 to choose from and you have to pick the correct one. eg ball, ball, ball, hat, nothing, hat, ball, ball, ball. correct picture would be hat. or you also get hard shapes in all different sequences and you have to work it out. This test stands on its own but is added to the others to make the composite IQ. if you child does well in this i would say this test in itself would determine how smart the child is as the others are more about language. this is why ESL students can be tested who cant speak English.
My guess is that your child may be struggling in reading but has a high comprehension. If so he may be struggling to put together the components required for reading. I would like to direct you to a web site in Australia by searching google "Best start assessment". Its actually what is used to test k-2 primary students and to assist the teacher in knowing where the child is at and how to teach that child. It takes a little working out but once you do you will be able to place your child in literacy continuum and assist the child in those areas.
having said that i realize you will not be able to get the resources through this site because it is a government site for teachers to access but it will give you the language to help you find those resources in your country.
All the best