Comparison among different measurement systems for fibrinogen using fresh samples and frozen samples.

Abstract Background Many laboratories in China have several types of coagulation analyzers. Differences in fibrinogen results among different systems may cause inappropriate medical decisions. Our aim was to set the comparability evaluation criteria and evaluate comparability of different fibrinogen measurement systems using fresh and frozen samples. Methods Biological variation (BV) publications on fibrinogen were reviewed. Total error based on reliable BV data and external quality assessment (EQA) criteria were combined to set allowable limit. The compliance rate of samples for the limit should achieve at least 80% if the results obtained from different systems were comparable. Fifty-seven samples before and after freeze–thaw were measured by three measurement systems and the percentage of compliant samples was calculated. Results The allowable limit was 11.3%. The compliance rates of fresh samples were 78.2%–84.2% , and the rates of frozen samples were 54.5%–93.0%. The comparability results were different using two kinds of samples. Conclusions It is feasible to set allowable limits of comparability based on BV and state of the art; and fresh samples are recommended for evaluating systems comparability. The results of comparability are related to samples’ concentrations distribution, which should range over the concentration ranges in routine laboratory tests.