Abstract Introduction/Objective Background: Antiphospholipid antibodies bind phospholipid bound proteins. Criteria for diagnosis of the antiphospholipid syndrome includes detection of either a lupus anticoagulant (LA) or anticardiolipin/anti B2GP1 antibodies and thrombotic events or pregnancy loss. Functional LA is detected by prolonged dRVVT clotting time (dCT) of patient plasma in the presence of limited phospholipid (screen) followed by a 1:1 mix of patient and normal pooled plasma to rule out procoagulant deficiency (mix). Confirmation is achieved by addition of excess phospholipid shortening the dCT and increasing the screen/confirm ratio (SCR). Normalization involves testing pooled reference plasma to determine the SCR with an added calculation step to correct for reagent/instrument differences. We compared the SCR in patient plasma with that obtained using reference plasma to determine impact on clinical decision making. Methods/Case Report Methods: 404 patients had dRVVT testing (STAGO STA-R Evolution) from 09/2021 to 05/2022. Positive screens (≥51 seconds) underwent mixing studies followed by confirmatory tests (>=46 seconds). The dRVVT of reference pooled plasma was also measured (George King Normal Pooled Plasma). A positive conventional or normalized SCR was defined as an SCR > 1.2 and comparison was by the paired t test. Results (if a Case Study enter NA) 6.4% (26) of the 404 samples tested were confirmed positive for LA by both methods, out of which 12 had a clinical history of thrombosis. Although a statistically significant difference between the two groups (p=0.0096) was found, the magnitude of absolute SCR differences (0.1s) was within total allowable error limits and there was 100% concordance of positive and negative results between the 2 groups. Conclusion There is no clinically significant difference between the two groups. Normalization had no benefit in our patient population, therefore no need for the extra calculation step. Others have reported that normalization is useful for inter-method and inter-laboratory studies and not for within method LA detection consistent with our results.