7. Spurious Counts and Spurious Results on Hematology Analyzers: Platelets
- Kandice Kottke-Marchant MD, PhD2,3,4,
- Bruce H. Davis MD5
Published Online: 8 AUG 2012
Copyright © 2012 Blackwell Publishing Ltd
Laboratory Hematology Practice
How to Cite
Zandecki, M., Genevieve, F., Gérard, J. and Godon, A. (2012) Spurious Counts and Spurious Results on Hematology Analyzers: Platelets, in Laboratory Hematology Practice (eds K. Kottke-Marchant and B. H. Davis), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781444398595.ch7
Pathology & Laboratory Medicine Institute, Cleveland, OH, USA
Department of Pathology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA
Hemostasis and Thrombosis, Department of Clinical Pathology, Cleveland Clinic, Cleveland, OH, USA
Trillium Diagnostics, LLC, Bangor, ME, USA
- Published Online: 8 AUG 2012
- Published Print: 10 APR 2012
Print ISBN: 9781405162180
Online ISBN: 9781444398595
- hematology analyzers;
- automated count;
- complete blood count;
- spurious count;
The widespread use of hematology analyzers has led to major improvements in cellular hematology because of the quick and accurate results that are obtained in most instances. However, in several situations spurious results are observed: inadequate blood samples, situations induced by the anticoagulant(s) being used, peculiar changes related to the pathology in the patient, and technical considerations about performances of the various hematology analyzers must be considered.
Spurious thrombocytopenia occurs in several circumstances related to the presence of ethylene diamine tetraacetic acid (EDTA) used as the anticoagulant. The mechanism of EDTA-dependent platelet agglutination is related to circulating (auto)antibodies directed against normally hidden epitope(s) in the glycoprotein αIIb/βIIIa complex from platelet membrane exposed only in the presence of EDTA. Other spuriously low platelet counts may be related to EDTA, including platelet rosetting around white blood cells (satellitism) and platelet-white blood cell aggregates, but mechanisms responsible for those latter phenomena are less well known.
A spurious increase in platelet count may be related to several situations, including fragmented red blood cells, cytoplasmic fragments of nucleated cells, cryoglobulins, bacteria or fungi, and lipids. Flags generated in several of these situations alert the operator to possible abnormal findings and may identify the problem. Analyzing only platelet parameters is not sufficient and in many situations the white cell differential scattergram is of crucial help for flagging abnormalities. The flags generated depend on the software version on the hematology analyzer used, the performance in detecting the same anomalies may differ according to which analyzer is used, even those from the same manufacturer. Operators must be aware of the characteristics of their analyzer and be able to recognize and circumvent anomalous results.