Kerri, if the PSA turns out to have gone from 0.005 to 0.01 it is still unlikely to be a concern - at these tiny levels, machine noise, one machine being calibrated or due for calibration, our consultant said it could be as minor as picking up a part cell on a slide rather than a full one. He also said that due to normal variance to half of one hundredth, a reading of 0.03 could actually be anything from 0.01 - 0.05 - i.e. if you put one blood sample into five different test tubes, it could produce 5 different results anywhere in that range.
I can see why nurse led clinics are required to check back to the consultant if someone's PSA rises over 0.1 but it still remains that 0.2 is the 'official' threshold for chemical recurrence. Belt & braces between 0.1 - 0.2 will be more likely if there were concerns after the path results, there have been successive rises or if the rise is rapid, if the patient is very anxious, etc