What conditions cause false positive for thc?

Just a few factors: Factors that interfere with test results include: apple juice, blood in urine, technical error, adulteration of specimen, lower cut off levels of screen etc. Confirmatory tests can be done if positive.

Thc urine mimics: Hemp seed oil, kidney disease, diabetes, liver disease and riboflavin, or b2, can be capable of causing a false positive result on a drug screen for marijuana. Documentation of the disease, or the pill bottle should be brought along to show to the laboratory staff during any drug testing. Marinol, nsaid's, protonix, (pantoprazole) can also cause false positives.