The agency also called out the company for failing to identify potential risk to patients from a falsely low test result.

Prozone is a known phenomenon affecting immunoassays causing falsely low or negative results when excess target is present in the test system.

Since the glycated abnormal Hb emerged at the same position as did HbF on high performance liquid chromatography, the HbA1C value was falsely low.

In the Form 483 on Thursday, FDA also noted that the company failed to adequately evaluate the risk of the test for falsely low results.