A paper by the think tank, co-authored by RCGP president Dr Iona Heath, says tests devised by social psychologists could be used to measure trust, interpersonal skills and responsiveness.
Existing patient surveys are 'too broad in scope to capture the subtle and intimate nature of the relationship,' it says.
Measuring Quality in the Therapeutic Relationship says that continuity of care has suffered as consultation length falls and patients register with practices, not individual GPs.
'Some suggest the tendency to audit and performance manage practitioners around standardised quality metrics has inadvertently driven down the quality of the GP-patient relationship,' says the paper.
Although the GP-patient relationship is hard to measure, the report suggests that 'there is merit in encouraging practitioners to study (and) improve their own contribution to it'.
Health secretary Andrew Lansley has recently called for an end to the GP patient survey in its current form as well as the 48-hour access target.
GPC negotiator Dr Chaand Nagpaul said the GPC would not oppose exploring alternatives to the patient survey. But he warned the DoH 'not to underestimate the complexity of measuring things like trust in the consultation'.