Inconclusive test result

What does an inclusive hep b test result mean?

I've had the Hep B vaccine done years ago and each time my results have been fine.  This last time my result was inconclusive.....What could have caused that?  Should I be concerned?  I've had my test repeated and am currently awaiting the results.

Could this be lab errors or false interpretation of results?
Any feedback is appreciated.

[cajim]

Yes, sometimes lab errors will give inconclusive results.  All you have to do is a repeat lab test.  

If your HBsAg is negative and hepatitis B surface antibody (anti-HBs) is positive, you are immune for life to HepB, why did you have to test again and again?

[Jazmineca]

Whenever I switch jobs, it is required for me to be tested each time (by different employers).  

Do inconclusive results happen often?

[cajim]

No, especially two consecutive inconclusive results.  So your next result should be accurate.

[Jazmineca]

My result was fine.  I believe it was lab error....blood collected in wrong tube.  Thanks to all for your input.