如何在PHP中处理'μg'?

So I am having problems with the symbol µg in PHP. The symbol is inside an array of data but I can't seem to match it with the following:

if($value == 'µg') {
    echo 'blah';
}

Does anyone happen to have a work around for this? I'm assuming PHP saves it as a different type then what I am comparing it to because it never echo's the 'blah' above. I have searched around for a while now and cannot find anything to help me. Thanks!

Okay so even with the help of some people I haven't found the answer.

The best I came up with that actually works is:

substr('µg', 1,7) == 'micro;g'

That's the only way I found out how to parse the data. If you put the & in front of the micro; you get the µ. A dirty fix but if anyone has a way around please let me know. Thanks!