Journal Information
Journal ID (publisher-id): BM
Journal ID (nlm-ta): Biochem Med (Zagreb)
Title: Biochemia Medica
Abbreviated Title: Biochem. Med. (Zagreb)
ISSN (print): 1330-0962
ISSN (electronic): 1846-7482
Publisher: Croatian Society of Medical Biochemistry and Laboratory Medicine
Article Information
Copyright statement: ©Croatian Society of Medical Biochemistry and Laboratory Medicine.
Copyright: 2022, Croatian Society of Medical Biochemistry
License (open-access):
This is an Open Access article distributed under the terms of the Creative Commons Attribution (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Date received: 19 October 2021
Date accepted: 29 April 2022
Publication date (print and electronic): 15 June 2022
Volume: 32
Issue: 2
Electronic Location Identifier: 020713
Publisher ID: bm-32-2-020713
DOI: 10.11613/BM.2022.020713
Assay validity of point-of-care platelet function tests in thrombocytopenic blood samples
Beate Eichelberger[2]
Peter Quehenberger[9]
Eva Schaden[1]
Marion Wiegele[1]
[1] Department of Anaesthesia, Critical Care and Pain Medicine, Division of General Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
[2] Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria
[3] Center for Physiology and Pharmacology, Institute of Vascular Biology and Thrombosis Research, Medical University of Vienna, Vienna, Austria
[4] Center for Medical Statistics, Informatics, and Intelligent Systems, Institute for Artificial Intelligence and Decision Support, Medical University of Vienna, Vienna, Austria
[5] Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
[6] Department of General, Visceral and Transplant Surgery, University Hospital Tübingen, Tübingen, Germany
[7] Department of Clinical Pharmacology, University Hospital Tübingen, Tübingen, Germany
[8] Cluster of Excellence iFIT (EXC 2180) “Image-Guided and Functionally Instructed Tumor Therapies”, University of Tübingen, Tübingen, Germany
[9] Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
Author notes:
The first two authors contributed equally to this work.
[*] Corresponding author: conrad.lacom@meduniwien.ac.at
Introduction
Point-of-care (POC) platelet function tests are faster and easier to perform than in-depth assessment by flow cytometry. At low platelet counts, however, POC tests are prone to assess platelet function incorrectly. Lower limits of platelet count required to obtain valid test results were defined and a testing method to facilitate comparability between different tests was established.
Materials and methods
We assessed platelet function in whole blood samples of healthy volunteers at decreasing platelet counts (> 100, 80-100, 50-80, 30-50 and < 30 x109/L) using two POC tests: impedance aggregometry and in-vitro bleeding time. Flow cytometry served as the gold standard. The number of platelets needed to reach 50% of the maximum function (ED50) and the lower reference limit (EDref) were calculated to define limits of test validity.
Results
The minimal platelet count required for reliable test results was 100 x109/L for impedance aggregometry and in-vitro bleeding time but only 30 x109/L for flow cytometry. Comparison of ED50 and EDref showed significantly lower values for flow cytometry than either POC test (P value < 0.05) but no difference between POC tests nor between the used platelet agonists within a test method.
Conclusion
Calculating the ED50 and EDref provides an effective way to compare values from different platelet function assays. Flow cytometry enables correct platelet function testing as long as platelet count is > 30 x109/L whereas impedance aggregometry and in-vitro bleeding time are inconsistent unless platelet count is > 100 x109/L.
Keywords: flow cytometry; platelet function; point-of-care tests; thrombocytopenia
