Abstract
Introduction Light transmission aggregometry (LTA) is regarded as the gold standard in platelet
function diagnostics. However, there is a relevant degree of interlaboratory variability
in practical applications.
Objective The aim of the present study was to develop a practicable laboratory comparison on
LTA and to analyze differences and influencing factors in regard to standardization
in five specialized hemostaseological centers.
Methods The study was performed on 30 patients in total. Each center performed LTA on blood
samples from six healthy volunteers (three men and three women) using the inductors
collagen (Col), adenosine diphosphate (ADP), arachidonic acid (ARA), and ristocetin.
The LTA was performed three times using different methods as follows: (1) International
Society on Thrombosis and Haemostasis recommendations with identical reagents, (2)
in-house protocols and the identical reagents; and (3) in-house protocols and in-house
reagents.
Results A total of 396 measurements of 30 probands were performed. Even after standardization
of the protocol and using identical reagents, there were significant differences between
the centers regarding the final and maximum aggregation (p = 0.002 and <0.001) and further significant differences in the maximum and final
aggregation according to the wavelength of the device used to measure the LTA (PAP-8:
430 nm, APACT 4004: 740 nm [p < 0.001 each]). Using identical reagents but individual inductor concentrations and
laboratory protocols also resulted in different maximum and final aggregation. The
largest differences were seen with Col and ristocetin; there were significant influences
from the reagents' manufacturers in the results of aggregometry for the inductor Col
(p < 0.01) but not for ADP, ARA, and ristocetin.
Conclusion In this study, we proved that there are significant influences from the used aggregometers,
inductors concentrations, and manufacturers. These results illustrate the challenges
and importance of standardization of LTA.
Keywords
inherited/acquired platelet disorders - platelet physiology - platelet immunology
- platelet glycoproteins