SHANGHAI - Education authorities have halted intelligence quotient (IQ) tests for students with low examination scores in Wuxi, East China's Jiangsu province.

Since January, some 500 primary school students with below-average exam scores have been told by teachers to take IQ tests at the Wuxi Children's Hospital, according to the Jiangnan Evening News, a Wuxi-based newspaper.

Zeng Laiyu, mother of a 7-year-old boy, said she was upset to get a phone call from her son's teacher in early October asking that the student have his IQ tested.

"My son is just as bright as the other students. He only got a 70 in math because he acts up in class instead of listening to the teachers. It is unfair and unethical for a teacher to ask my son to prove he's not smart," said Zeng.

Zeng said she didn't have her son's IQ tested, calling the request "simply absurd".

Zhang Feng, director of the children's healthcare department at the hospital, refused to comment on Sunday on IQ tests conducted in the department.

Zhang was quoted by the Jiangnan Evening News on Oct 25 as saying that about 70 percent of the IQ test results of the students in the hospital were normal.

Some of the results fell between 65 and 70 on a scale of 130, while just a few results were below 65.

The regulations state that if a teacher can obtain a diagnosis of a student saying that the child's IQ is below 70, the teacher can apply to the school to exclude the student's academic performance from the assessment of teaching quality, a source with the Wuxi education authorities told China Daily.

In many primary schools in Wuxi, a teacher's performance-based salary is closely related to students' academic performance, or more precisely, students' exam scores, said the source.

"Teachers worry that low student scores would hurt their income, so they resorted to asking students to obtain a diagnosis saying that the children were stupid, which was wrong indeed," said the source.

Wuxi education authorities and the education supervision office of the Wuxi government jointly released a circular on Oct 28 banning such tests.

It is wrong to evaluate students' learning ability and potential only based on their IQ test performances, and it violates the rules of education to do so, said the circular.

Authorities will launch an investigation of schools and teachers that ordered IQ tests as a means of demonstrating low intelligence, the circular said.

Schools and teachers that are found to have taken part in this practice will not be eligible to be designated as excellent units or individuals in various competitions, according to the circular.