Different countries (or labs), different levels of Normal ...

Hi, I've been having a few issues with some raised liver enzymes levels, but am asymptomatic. I've got slightly raised ALT and lipase enzymes and also high B12. I've had an abdominal ultrasound to check my pancreas and all was fine.

In my research I've noticed that different countries have different cut off levels for normal results. An example of this is with B12, in NZ the normal levels are 170-600 and mine is 644 (has been 778) which is high. In other countries, the normal is 200-900 which would put me within the normal range.

Another is lipase, in NZ the normal range is 16-67 (mine is currently 76), but other countries have normal levels of 23-85 or even 0-160 depending on the laboratory.

ALT in NZ is < 45 (mine is currently 48), in other countries the normal is <56.

I'm wondering if the various normal levels are dependent on the population of that country, in NZ we only have a population of 4.7 million.

I've found this comforting but also somewhat worrying! The experience of being told I have abnormal test results has been very stressful. Of course all our levels should be within a certain range but we all have things go wrong with us from time to time or when we age. I have autoimmune issues which I strongly believe are responsible for my increase in lipase and ALT levels. I'm not so concerned about my B12 levels when looking at the 'other countries' levels.