Audit of accuracy of clinical coding in oral surgery

We aimed to study the accuracy of clinical coding within oral surgery and to identify ways in which it can be improved. We undertook did a multidisciplinary audit of a sample of 646 day case patients who had had oral surgery procedures between 2011 and 2012. We compared the codes given with their case notes and amended any discrepancies. The accuracy of coding was assessed for primary and secondary diagnoses and procedures, and for health resource groupings (HRGs). The financial impact of coding Subjectivity, Variability and Error (SVE) was assessed by reference to national tariffs. The audit resulted in 122 (19%) changes to primary diagnoses. The codes for primary procedures changed in 224 (35%) cases; 310 (48%) morbidities and complications had been missed, and 266 (41%) secondary procedures had been missed or were incorrect. This led to at least one change of coding in 496 (77%) patients, and to the HRG changes in 348 (54%) patients. The financial impact of this was £114 in lost revenue per patient. There is a high incidence of coding errors in oral surgery because of the large number of day cases, a lack of awareness by clinicians of coding issues, and because clinical coders are not always familiar with the large number of highly specialised abbreviations used. Accuracy of coding can be improved through the use of a well-designed proforma, and standards can be maintained by the use of an ongoing data quality assurance programme.