Clinical BERT pre-trained on MIMIC corpus has been reported to have superior performance on NER tasks in Inside-Outside-Beginning (IOB) format (Ramshaw and Marcus, 1999) using i2b2 2010 (Uzuner et al., 2011) and 2012 (Sun et al., 2013) data<cite> (Alsentzer et al., 2019)</cite> .Original training/development/test splits in the challenges were used.