Can I refuse a drug test with childrens protective services if I have already passed the other ones?

I was not suppose to take my daughter to my mom's house unless they passed their hair folicule test for meth. I knew my dad did but we were waiting on my mom's. My mom finally got hers yesterday and she told me she had passed and I believed her. Well my mom asked if I would drop my daughter off while I went to town so everyone could visit so I did. We were all getting along. When I got back from town my mom would not give her to me so I called the police. She had lied, she did not pass her hair folicule test. So because she was forced to give me back my daughter she is going to call my caseworker and tell her that I am on drugs,to come give me a drug test. I passed the first drug test and they know I'm not on drugs the even denied me a hair folicule because they said it was not nessecary. So if they come here to drug test me over my mom being crazy, could I refuse to take it? I don't have any problem taking a drug test but I think I have rights to refuse one because of heresay/revenge on me.