Accidentally ate hash during mpu?

I'm currently at a colleague's house, and he made himself some muesli with hash cake. I ate two spoonfuls of it, and when I asked him if there was anything in it, he said no. There were just tiny pieces of cake in it. I just found out this morning. The biggest problem is that I have a hair sample in a few days for the MPU (medical examination). Will it be reported if I eat one of those tiny pieces? And is there a threshold for a hair sample?