Chapter 18 - Sources of errors in hematology and coagulation

Abstract

Hematology tests such as complete blood count and peripheral blood smear analysis are commonly ordered test in clinical laboratory ,and sources of errors in such tests could be preanalytical, analytical, or postanalytical. Errors related to sample collection, transport, and storage must be avoided to get accurate results in hematology testing. The amount and concentration of dipotassium ethylenediaminetetraacetic acid (EDTA) in the collection tube require that blood should be collected up to a specific mark on the tube. If too little blood is collected, dilution of the sample can become an issue with alteration of parameters. Relative excess EDTA in such cases also affects the morphology of blood cells. Transport of specimen should ensure that high temperatures are avoided. Red cell fragmentation is a feature of excess heat. Falsely high white blood cell (WBC) counts are more common than falsely low WBC counts. In certain situations, hematology analyzers are known to provide a falsely low platelet count when the true platelet count is adequate. Other common sources of errors in hematology and coagulation tests are also discussed.