MM-736 Optimizing Outpatient Referral Pattern for Monoclonal Gammopathy at a Safety-Net Hospital

Serum monoclonal protein (SPEP) testing using an expanded panel that includes free light chains (FLC) aids in the diagnosis and monitoring of monoclonal gammopathies, which are precursor conditions to myeloma. Any values outside of reference ranges for serum kappa (k) (3.3-19.4 mg/L) FLC and lambda (l) (5.7-26.3 mg/L) FLC and FLC ratio (R) (0.26-1.65) can trigger referrals to hematology. To compare the current standard FLC results of patient samples at John Peter Smith (JPS) hospital against the revised definition presented at the American Society of Hematology 2023 conference by the Istoppm study group. We conducted a retrospective study (North Texas IRB # 2188238-1) using data from JPS Data Analytics. All SPEP results, including FLC, were obtained from 1/1/2022 to 12/31/22. We analyzed k, l, and R using standard criteria from outpatient orders placed by rheumatology, nephrology, neurology and all others excluding oncology. We then used the revised FLC definition and algorithm and compared the number of abnormal tests and referrals to hematology. JPS is a safety-net hospital in north Texas. A group of 5 general hematology-oncology physicians and 7 mid-level providers manage care of patients with all malignancies, benign hematology, and precursor conditions. Change in FLC ratio and referral pattern based on revised definition. 1028 samples involving 763 patients were included. Abnormal sample results per standard criteria were as follows in the order k, l, R and any of these three/total: rheumatology: 133, 57, 24, 136/177 (76.8%); nephrology: 123, 146, 80, 163/243 (67.1%); neurology: 99, 22, 23, 105/159 (66.0%); all other samples: 371, 181, 116, 378/449 (84.2%). Overall, 76.1% of all FLC samples and 23.6% of R were abnormal by standard criteria. Using the revised criteria, 27 samples had an abnormal R. Previously, 191 referrals were placed to hematology. Using revised criteria, only 10 would need referrals and 7 had referrals placed. Applying the revised Istoppm FLC definition significantly decreased the number of abnormal results. This would decrease the number of unnecessary referrals to hematology while ensuring that the patients who have true myeloma precursor conditions are referred and followed appropriately.