Objectives: To investigate whether discharge summaries are accurately coding clinical details of patient admissions and to identify whether such differences lead to a loss of financial income for acute trusts. Design: A cross-sectional study of medical records, discharge summaries and financial outcomes. Participants: A review was conducted of two weeks of discharge summaries and patient notes from the stroke unit, totaling 95 patient episodes. Results: The total number of medical details not coded in discharge summaries was 580, resulting in a loss of income of £17,488.38. Extrapolated over the year, this could have led to a missed income of £454,000 for the stroke department. Sub-group analysis identified that 24% of un-coded details were extra primary diagnoses, 45% secondary diagnoses, 14% social factors, 3% investigations performed, and 14% were specialty team reviews. Conclusions: The impact of the quality of discharge summaries has proven to be huge. A major contributor is unawareness of the correct terminology by both clinical and coding teams. Specific measures to introduce standard diagnoses and coding practices to minimise variability will lead to clearer coding and allow for the trust to be accurately paid for the care performed.