(CNN) Some of the coronavirus test kits shipped to labs across the country are not working as they should, the US Centers for Disease Control and Prevention said.

As a result, the CDC is remaking parts of the test kits after some produced inconclusive test results.

The kits were sent to the states to speed up the testing process, the CDC's Nancy Messonnier told reporters Wednesday . The states found out the flaw during the verification process. For quality control, when states get any test kit, they first verify that it works.

"When some states were doing this, we received feedback that they weren't -- that it wasn't working as expected, specifically some public health labs at states were getting inconclusive results and what that means is that test results were not coming back as false positive or false negatives, but they were being read as inconclusive," Messonnier said.

Some states notified the CDC that they were unable to validate the test, and the agency is remanufacturing a reagent used in the test that's not performing consistently.

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