B-035 Atellica CI Analyzer Sample-to-sample Carryover Performance Evaluation

Abstract Background Laboratories in many parts of the world are required to demonstrate/confirm the lack of sample carryover on their analyzer under their laboratory conditions using patient populations. Sample carryover occurs when analyte adheres to the probe and/or cuvette and contaminates a subsequent sample or cuvette in the testing sequence of the analyzer. Inadequate washing of the sample aspiration/ dispensing device and cuvette can cause this type of carryover. The Atellica® CI Analyzer uses independent integration and random-access sampling to process chemistry (CH) and immunoassay (IM) tests. The immunoassays performed on the IM portion of the analyzer utilizes a single-use, disposable sample tip and reaction cuvette which reduces sample carryover from IM to CH tests, whereas a reusable probe is used for CH assays—which is washed between sampling. This study evaluated the potential for carryover of CH samples from one sample to the next due to washing protocols on the Atellica® CI Analyzer in four independent real world clinical laboratories. Methods Carryover verification was performed as per CLSI GP31-A:2009 and Vericheck protocols. The study was conducted at four sites (UAE, France, Croatia, U.S.) using 2 serum samples prepared in 12 sample containers-9 for low (L) and 3 for high (H) concentrations of analyte. For glucose (GluH_3), UAE, L and H were 63 and 356 mg/dL (3.5 and 19.8 mmol/L), Croatia, 77.4 and 237.5 mg/dL (4.3 and 12.2 mmol/L), and U.S., 101 and 374 mg/dL (5.6 and 20.8 mmol/L). For creatine kinase (CK_L), France, L and H were 40 and 1400 U/L. Samples were tested in a defined sequence: L1, L2, L3, H1, L4, H2, L5, H3, L6, L7, L8, L9 and results analyzed for % carryover. Carryover was defined as average of L4, L5, L6 minus the average of L1, L2, L3, L7, L8, L9 divided by the average of H1, H2, H3. Results No significant carryover was observed at any site. Carryover % for UAE, France, Croatia, and U.S was 0.500%, -0.085%, -0.095%, and -0.095%, respectively. Conclusions When using high positive samples at concentrations at or greater than the upper limit of the clinical range, negligible CH sample carryover was found from the Atellica CI Analyzers in four independent real world clinical laboratory settings.