What did you blow into - a handheld plastic tube with numbers that go up when you blow, or a tube connected to a machine that usually requires 3 good long blows with the person performing the test encouraging you to 'keep going'?.
COPD is usually diagnosed though a persons medical/social history, (ie) have they ever smoked, the work they have done and then performing a spirometry and having someone who is qualified to read the results and then diagnose any conditions.
Sometimes where the diagnosis is in question the person performing the test will ask you to take an inhaler of a reliever drug called Ventolin or Salbutamol, wait approximately 20 minutes and perform the test again. If the test results improve by a specific amount then Asthma may be diagnosed. A chest X Ray may also be performed.
COPD cannot be diagnosed through a peak flow meter.
I hope this is helpful - as always please call us on 03000 030 555.