The UCLH paper last October said that during the course of its contract negotiations with IDX, the supplier gave assurances to the trust that its product was fully compliant with NHS data requirements.
"In fact the product did not comply with the NHS data model," said the paper. "Completion of the mapping of the IDX product to the data model is a continuing cause of delay to the project.
"The mapping is important because it ensures that the correct data is collected, recorded and extracted for Department of Health returns and for primary care trusts to support income recovery."
Now, however, UCLH said the IDX product conforms with NHS data requirements.
The paper also said, "We had anticipated that the project we were going to be doing was the implementation of an existing product, but it has in fact turned into a software development project."
Robert Baker, managing director of IDX Systems UK, said, "Subsequent to signing our contract with UCLH, we made the joint decision with UCLH to implement IDX Carecast, our newest and most sophisticated solution, which was then under development.
"In such a development project, some delays are to be expected in return for the benefits of a new solution.
"We expect a successful go live for Carecast with the entire UCLH complex in April."