The 18-page booklet from the General Practice Airways Group (GPIAG) advises GPs to use reversibility testing to differentiate between asthma and COPD patients.
Under the quality framework GPs can earn five points for doing this, but NICE COPD guidelines say history and longitudinal observation should be used instead.
Dr Kevin Gruffydd-Jones, a Wiltshire GP who co-wrote the GPIAG booklet, said: 'The NICE guidelines are more suitable for secondary care.
'We are faced with having to make differential diagnoses of asthma and COPD. Reversibility testing is the best way to do this.'
He added that a GPIAG survey had found that more than half of GPs were not following NICE guidelines because they were unaware of or confused by them.
The GPIAG guide differs from the NICE guidelines in that it emphasises the secondary effects of COPD, such as depression, muscle weakness and reduced quality of life.
There is also a chart summarising all treatment options for the condition and associated problems.
In particular, the importance of palliative care for advanced COPD patients is emphasised because studies have shown that they receive worse care than those with terminal lung cancer.