My husband was just refused a job because his urine tested clean but was 1 degree to hot.

this is unclear to me . If the urine was clean why should he be refused the job. What difference does it make the temperature of the urine?

They probably saw that as an indication the sample had been altered trying to beat the test. You can't pee warmer than your body temp. If he has an explanation for how that could have happened, he should tell them. If he set the sample on a radiator while he tied his shoe or cleaned the outside of the cup with hot water to remove spillage, they might be willing to do a retest.