"Concerned that 'no test was ever taken'"

I had taken an overdose. I had taken a fair few of these over a relatively short period and was known in the Selly Oak Hospital A+E dept. A year or so ago, I read my medical notes and saw something that shocked me. There was a time when I had taken an overdose and one doctor had written in my notes that I was to be discharged after a 'negative test result'. Then the next thing I read on the same paper was that a doctor had said there was a negative result when 'no test was ever taken'. In my opinion this is negligence and however ‘difficult’ a patient is, this could have been very dangerous had the overdose worked.