A little lab lost

We were inspected recently and did not have any UoM for Diamed systems, which they had no issue with.  We do however have a table in the SOP listing mitergation of uncertainty for the analysers but no actual calculations and they were happy that we had considered it.  I think in the standards it says to 'consider' uncertainty so we listed things like IQC, EQA, competency assesment of users, 3rd party controls, standard reagents that have a BAT etc. 

If antibody screen is positive  and if we have upto date record  of  prophylaxis anti-D than we report as AntiD detected due to prophylaxis or sensitizing event. Please check history and  confirm with clinician. BUT If patient has sensitizing event prior to 28  weeks we treat as immune antiD and send sample for quantification  and continue antenatal and postnatal prophylaxis. 

Please help. I have read around the subject of uncertainty of measurement to comply with ISO15189, but I am still not any wiser.
i don't think I am allowed to declare any uncertainty about my blood group results as this should not be variable otherwise my parents would be in trouble. But what about that anti-E that disappears with time? Only to re-emerge after a 2 unit transfusion at another hospital ??
Has anyone had that awkward conversation with the assessor about uncertainty with their results?
 
 

This made my brain hurt and gave me nightmares of Chemistry and College Algebra.

there was an article on this in the last issue of the biomedical Scientist.  When I read it, I have to confess,
a - I didn't really understand the point and
b - moved one step nearer to total despair about the useless requirements that might have sense in chemistry but in IH just get in the way of doing useful work
I'm ranting again