MPs on the Health Bill committee last week finalised amendments to the Bill ahead of its final reading in the House of Commons.
But evidence heard at the same time by health select committee MPs demonstrates the scale of uncertainty and concern that remains over changes to NHS funding.
MPs heard that aggressive consortia could 'cherry pick' practices which attract the most money or the healthiest patients. Practices themselves may 'cherry pick' patients that require the least work, experts warned.
The DoH has given little indication of what the funding formula for consortia might look like, fuelling speculation about its impact and fears that it will not be ready on time.
Margaret Whitehead, professor of public heath at the University of Liverpool, told the health select committee last week that devising a funding formula for GP consortia would be 'a big problem'.
Consortia will start choosing their constituent practices according to how much money their patients cost them, said Professor Whitehead - who also advises the DoH's Advisory Committee on Resource Allocation.
'PCTs have responsibility for all people resident in a defined geographic area. That is an incredible protection against cherry picking, said Professor Whitehead. 'You don't have that constraint with consortia.You have GP practices coming together and choosing which of their colleagues to work with in consortia.
'You can get some practices shunned because of their patients. You can have some, perhaps from more affluent areas encouraged to join.'
It was theoretically possible that the abolition of practice boundaries could see practices start 'cherry picking' patients too, she said. 'Whether it would happen in practice is another matter,' she added.
Patient strain on budgets
RCGP chairwoman Dr Clare Gerada has voiced similar concerns; that GPs will start to see patients with complex needs as a strain on their budgets.
'If Mrs Jones comes to me with chronic renal failure ... there may well be no one that can mandate me to take on this high cost patient,' she told the Health Bill committee in February. Dr Gerada has also suggested consortia could have to interview patients to see if they can afford to take them on.
But other experts say these concerns are exaggerated. Health consultant Noel Plumridge told MPs consortia might be tempted to shun patients who do not comply with treatment, but not those who are ill.
'There might be some reluctance to take on the person who has for instance, emphysema, but is unwilling to take some of the measures that might mitigate the symptoms,' he said.
Andy McKeon, managing director for health at the Audit Commission, said models being developed for the DoH will accurately predict the total cost of individual patients' treatment - meaning consortia should not have to worry about expensive illnesses. 'A possible way of doing this is to use the method known as person-based resource allocation,' he told MPs.
Developed by the Nuffield Trust, the model takes data on individual patients' treatment over two years and makes a prediction about their costs to the NHS in the following year.
However, Professor Whitehead said there was still 'a lot of work to do' on this model, which would need extensive testing before being used.
Abolition of PCTs
PCTs are due to be abolished by 2013, when consortia will receive their first full budget.
But Professor Whitehead said there was a chance it 'won't be ready in time'.
GPC negotiator Dr Peter Holden has said that to predict the cost of individual patients' treatment would be 'incredibly intrusive' and raise patient confidentiality issues.
There are yet more unanswered questions, such as how PCT deficits will be divided among consortia. The DoH has also been slow to produce a workable system for abolishing practice boundaries, which will only add to the complexity of the eventual funding.
The government must answer these questions, and soon. Many GPs will be alarmed that such fundamental issues have yet to be worked out as MPs prepare to pass the Health Bill on for scrutiny by the House of Lords.