Verifying measurements on Siemens Atellica® instruments using clinically acceptable analytical performance specifications.

Abstract

Measurements on clinical chemistry analysers must be verified to demonstrate applicability to their intended clinical use. We verified the performance of measurements on the Siemens Atellica® Solution chemistry analysers against the clinically acceptable analytical performance specifications, CAAPS, including the component of intra-individual biological variation, CV_I. The relative standard uncertainty of measurement, i.e. analytical variation, CV_A, was estimated for six example measurands, haemoglobin A_1c in whole blood (B-HbA_1c), albumin in urine (U-Alb), and the following measurands in plasma: sodium (P-Na), pancreatic amylase (P-AmylP), low-density lipoprotein cholesterol (P-LDL-C), and creatinine (P-Crea). Experimental CV_A was calculated from single-instrument imprecision using control samples, variation between measurements on parallel instruments, and estimation of bias with pooled patient specimens. Each obtained CV_A was compared with previously developed CAAPS. The calculated CV_A was 1.4% for B-HbA_1c (CAAPS 1.9% for single diagnostic testing, CAAPS 2.0% for monitoring after duplicate tests; IFCC units), 10.9% for U-Alb (CAAPS 44.9%), 1.2% for P-Na (CAAPS 0.6%, after triplicate testing 1.5%), 8.2% for P-AmylP (CAAPS 22.9%). The CV_A was 4.9% for P-LDL-C (CAAPS for cardiovascular risk stratification 4.9% after four replicates), and 4.2% for P-Crea (CAAPS 8.0%). Three of the six measurands fulfilled the estimated clinical need. Results from P-Na measurements indicate a general need for improving the P-Na assays for emergency patients. It is necessary to consider CV_I when creating diagnostic targets for laboratory tests, as emphasised by the CAAPS estimates of B-HbA_1c and P-LDL-C.