Pre-analytical Variables in Coagulation Testing Associated With Diagnostic Errors in Hemostasis

Emmanuel J. Favaloro, PhD, MAIMS, FFSc (RCPA); Dorothy M. (Adcock) Funk, MD; Giuseppe Lippi, MD


Lab Med. 2012;43(2):1-10. 

In This Article

Abstract and Introduction


The use of modern laboratory instrumentation with high levels of test reliability and appropriate quality assurance measures will lead to very few analytical errors within hemostasis testing. Nevertheless, incorrect or inappropriate test results are still reported, often due to events outside the control of the laboratories performing the tests. This is due primarily to pre-analytical events associated with sample collection and processing, as well as post-analytical events related to the reporting and interpretation of test results. This review focuses on the pre-analytical phase, highlighting contributory elements and providing suggestions on how problems can be minimized or prevented, thereby improving the likelihood that reported test results actually represent the true clinical status of the patient rather than that of an inappropriate sample. This review should be of value to both laboratory personnel and clinicians because an appreciation of these issues will enable the optimal clinical management of patients.


Modern instrumentation is generally capable of providing highly accurate test results. Utilized with appropriate internal quality control and external quality assurance measures, analytical errors within hemostasis testing are generally minimal. Nevertheless, incorrect or inappropriate test results will on occasion be reported to clinicians, most often due to circumstances beyond the control of the laboratories performing these tests. Overall, a significant impact on patient care arising from diagnostic errors has been estimated to arise in around 9% to 15% of errors, while the likelihood of inappropriate care has been described in 2% to 7% of such cases.[1] Many of these errors will originate due to the inappropriate collection, handling, or processing of samples referred for testing and sometimes because testing has been initiated on the wrong patient or at the wrong timepoint. In these instances, test results will accurately reflect the status of the test sample, but conversely they will not accurately reflect the clinical status of the patient being investigated. These issues are referred to as pre-analytical variables.


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