The FDA said an outside lab that reported very high levels of a carcinogen in ranitidine products used an "unsuitable" testing method, causing misleading results.
In a statement released Oct. 2, the FDA said Valisure used higher temperatures in its ranitidine testing than the agency's approved method. The higher temperatures caused more of the carcinogen, N-nitrosodimethylamine, to form than under normal conditions.
The FDA's testing, which uses lower temperatures that mimic the reaction ranitidine has when inside a human stomach, showed much lower levels of ranitidine than Valisure's testing.
However, the agency still called the level of NDMA in the drug "unacceptable."
Because of Valisure's misleading results, the FDA asked drugmakers to conduct their own testing and submit samples of their ranitidine products to the agency to be tested.
The statement comes as retailers like Walmart, CVS, Walgreens and Rite Aid remove ranitidine products from their shelves due to the discovery of the cancer-causing substance.
Read the full statement here.