Definitely second your comment. On my (small) half yearly checkup I failed the urine test, they told me to redo it and drink more before submitting it.
I put my sample on a desk with ca 50 others and they promptly lost it (;-))
Well, I was on my way to Europe when they realized it so I did the test here in Austria and sent the results, No problem...and a merry Christmas to you all
BTW: CAAC Hospital PEK