7953 Testosterone II (TSTII) Immunoassay Meets the CDC HoSt Certification Requirements for a Fourth Consecutive Year

Abstract Disclosure: K.N. Nissen: Employee; Self; Siemens Healthineers. N. Parker: Employee; Self; Siemens Healthineers. P. Samantha: Employee; Self; Siemens Healthineers. J.M. Rhea-McManus: Employee; Self; Siemens Healthineers. V. Shalhoub: Employee; Self; Siemens Healthineers. J. Freeman: Employee; Self; Siemens Healthineers. Background: The Atellica® IM and ADVIA Centaur® Testosterone II (TSTII) assay is enrolled in the CDC Hormone Standardization (CDC HoST) Certification Program, which is traceable to the primary testosterone Standard National Measurement Institute (NMI) M914. Certification is a yearlong process of 40 blinded samples from the CDC, 10 to be tested each quarter. If 4 consecutive quarters meet the bias acceptance criteria of ± 6.4%, CDC certification is achieved. The TSTII assay is standardized using internal standards made from United States Pharmacopea (USP)-grade testosterone. Standards are traceable to ID-LC-MS/MS by method comparison using CDC samples; ID-LC-MS/MS is traceable to the primary testosterone standard NMI M914. Methods: Initially, to standardize the assay, approximately 120 samples were obtained from CDC with CDC HoST ID-LC-MS dose values to value assign master curve standards. Multiple ADVIA Centaur TSTII reagent lots were tested with the CDC patient samples. Internal master curve standards were assayed as unknowns and dose values assigned using the RLU (system generated units–Relative Light Units) to CDC ID-LC-MS dose relationship. From 2019 to 2023, after standard value assignment, at least 179 individual patient samples from the CDC with blinded amounts of testosterone have been tested across all platforms. Each quarter, 10 blinded samples were tested in duplicate over 2 days. Results were analyzed by the CDC according to CLSI EP9-A2 for bias. Results: Correlation between the CDC assigned values and the Atellica IM, ADVIA Centaur, and ADVIA Centaur CP TSTII assay results was strong across all quarterly blind trials from 2019 to 2023 combined—Atellica IM intercept = +0.5 ng/dL, slope = 1.03, r = 0.990, n = 180, Bland Altman mean bias was 4.55%; ADVIA Centaur intercept = +0.3 ng/dL, slope = 1.04, r = 0.993, n = 179, mean bias was -0.27%; ADVIA Centaur CP intercept = +0.9 ng/dL, slope = 1.07, r = 0.993, n = 180, mean bias was 1.26%. The TSTII assay bias on all systems was consistently <6.4%. This enabled the TSTII assays to be CDC certified for a fourth consecutive year. Conclusions: The TSTII assay has consistently achieved CDC certification from 2019 to 2023. Siemens Healthineers is the only testosterone immunoassay manufacturer to be currently certified and has achieved certification for four consecutive years. Presentation: 6/1/2024