Radiometer has become aware of a potential issue with abl800 basic and abl8xx flex analyzers with software versions below v6.19 mr2 and configured to report cna+. We have received sporadic incidents of positive and negative biases for cna+, that potentially could lead to serious health consequences. The issue may show when using specific micro measuring modes. The issue is caused by a combination of software and analyzer specific hardware related to sample transport. Recall start date: May 10, 2022