What would cause a urine test to come negative for methadone?

A urine test may come back negative for methadone if the drug is not present in the system at the time of testing, possibly due to insufficient dosage, rapid metabolism, or recent cessation of use. Additionally, the specific testing methods used can influence results; some standard tests may not detect methadone, especially if the test is not designed for it. Factors like dilution from excessive fluid intake or the use of substances that mask drug presence can also lead to a negative result.