Background Confirmatory testing of SARS-CoV-2 results is essential to reduce false positives, but comes at a cost of significant extra workload for laboratories and increased turnaround time . A balance must be sought . We analysed our confirmatory testing pathway to produce a more refined approach in preparation for rising case numbers . Methods Over a 10-week low prevalence period we performed confirmatory testing on all newly positive results . Turnaround time was measured and results were analysed to identify a threshold that could be applied as a cut-off for future confirmatory testing and reduce overall workload for the laboratory . Results Between 22/06/20 and 31/08/20 confirmatory testing was performed on 108 newly positive samples, identifying 32 false positive results (30 %). Turnaround time doubled, increasing by an extra 17 hours . There was a highly statistically significant difference between initial Relative Light Unit (RLU) of results that confirmed compared to those that did not , 1176 vs 721 (P <0.00001). RLU = 1000 was identified as a suitable threshold for confirmatory testing in our laboratory: with RLU ≥ 1000 , 55/56 (98 %) confirmed as positive, whereas with RLU <1000 only 12/38 (32 %) confirmed . Conclusions False positive SARS-CoV-2 tests can be identified by confirmatory testing, yet this may significantly delay results . Establishing a threshold for confirmatory testing streamlines this process to focus only on samples where it is most required . We advise all laboratories to follow a similar process to identify thresholds that trigger confirmatory testing for their own assays, increasing accuracy while maintaining efficiency for when case numbers are high.