It's probably changed a lot since I used to work in that role when I first started working in the NHS, but I did that about 15 years ago. The main part of the job is to interpret every patient episode into standardised codes set by the world health organisation, the diagnostic codes were listed in a book called International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) which are supplied to the staff. Examples of the sort of codes would be J18.0 - Bronchopneumonia, S72.0 - Fracture of neck of femur etc. Your not expected to be an expert on medicine, it's not a particularly high paid job, but you'll receive training to help. And on a day-to-day basis you would speak to a variety of staff including doctors and nurses to help understand complex cases. The purpose of converting these records into codes is to allow statistics to be compiled regarding all the episode coming in to the hospital. This can be used for research, managing workflow and resourcing within the hospital. The pay isn't exciting, I'm sure it was band 3/4 at the time so around 20-25k roughly. And in terms of progression there wasn't much beyond the basic role.
But I've been working in clinical science for the past 15 years so it's probably changed a fair bit since I last did that role. Hope that helps a bit.
