only use half of the sample?

i did my pre-employment urine test and filled to the 60 ml line. she poured half of it into a bottle and had me throw the rest away.


why did she only use half the sample? I thought they had to do two test.

Thanks in advance!

30 mls is enough to do two tests, immunoassay then any non negative immunoassay gets a GC/MS, 15 mls each. The second sample, the B sample, or split sample, is optional, not a requirement.

thanks!