Establishing ongoing quality assurance in a retinal screening programme

Aim To establish a clinically efficient, cost-effective quality assurance programme as part of a routine retinopathy screening service. Methods The operation of a quality assurance system as part of an ongoing retinal screening service is described. A random selection of 12% of images of all people reported to have retinopathy and of 2% reported to have no retinopathy are re-graded by a consultant ophthalmologist. Entry of the two sets of data into a purpose-designed E.XCFL spreadsheet allows automated calculation of sensitivity and specificity. Results The results of quality assurance from August 200 1 to July 2003 are reported. Out of 8351 screening episodes, 498 were re-examined. Of the 62 cases identified by the ophthalmologist as having referable retinopathy. four false negatives for detection were identified. Three of these had been assigned to early re-screening by the retinal screener but were still regarded as false negative by the parameters of the quality assurance system. The sensitivity and specificity for detection of sight-threatening retinopathy were 93.5% (95% CI = 84.3-98.2%) and 97.8% (95% CI = 95.8-98.9%), respectively. Conclusion A robust and cost-effective system has been developed to allow monitoring of performance of routine retinal screening which may be extended to meet current national recommendations.