A crucial system that underpins the Government's £2.3bn IT health strategy - a new standard for the coding of medical terms by the end of 2001 - could be delayed.
The Government announced in 1999 that the first version of Snomed CT - a medical thesaurus of diseases and health problems - would be available by the end of 2001. It is due to incorporate work on a US standard dubbed Snomed and Read Codes, a UK computerised list of medical terms which has been under development since the early 1990s.
But the Building the Information Core strategy document published this week gave no commitment to the 2001 deadline and said Snomed's introduction is still subject to "a programme of testing to ensure that it can be implemented".
A Department of Health spokesman declined to comment on whether the 31 December 2001 target would be met. He said the matter is "under negotiation".
Specialists believe the adoption of a standardised method of categorising ailments is crucial to the future of business IT developments in the NHS. Without such a system, it is difficult for doctors and statisticians to analyse common causes and treatments of health problems.
Its absence could also hamper the development of electronic health records, which are key to Government plans for new NHS IT systems.
The Building the Information Core document said, "The use of a modern set of clinical terms underpins many aspects of the development of health information systems."
But it has been suggested that the integration of Read Codes and Snomed is proving more challenging than first thought.
Some experts believe the full implementation of Snomed - including training and allowing time for thousands of GPs to switch from Read Codes to the new system - could take years.
The development of a standard coding method for describing diseases has been characterised by uncertainties, mismanagement and wasted money.
In 1998 the National Audit Office attacked the NHS Executive's management of the Read Codes project. The scheme was invented by James Read, a GP whose private company became a beneficiary of NHS money on the project.
Although there are uncertainties over the adoption of Snomed, the Building the Information Core document made it clear that the UK work on Read Codes will be scrapped by 2003. "Users/suppliers are advised not to develop new Read Code-based systems from April 2003," it said.