Mean Platelet Volume and Plateletcrit Values May Not Be Associated With the Severity of Preeclampsia

I read with great interest the study by Peng et al. which examined the relationship between coagulation and platelet parameters and pregnancy outcome in patients with preeclampsia [1]. In this study, it was found that platelet count, mean platelet volume (MPV), and plateletcrit (PCT) values were significantly reduced with the severity of preeclampsia, and the researchers argued that their study showed a significant relationship between coagulation and platelet parameters and the severity of preeclampsia and adverse pregnancy outcome. I want to emphasize the existence of some factors that negatively affect the evaluation of platelet parameters in this study.

Since the measurement of MPV, a platelet parameter, has not yet been standardized, the use of these values for purposes such as diagnosis or prognosis, especially in acquired diseases, is definitely not recommended [2]. The main factors affecting MPV measurement standardization are the type of anticoagulant used in the measurement, the time between blood collection and measurement, and the devices used in the measurement [3-5]. As in this study, the most commonly used anticoagulant in complete blood counts is ethylenediaminetetraacetic acid (EDTA), and when platelets come into contact with EDTA in the blood tube, they undergo rapid growth, change shape, and develop pseudopods [3]. The increase in MPV caused by EDTA contact can be up to 30% in the first 5 min and 40%–45% in the first 2 h [3]. In studies using EDTA as an anticoagulant, increases of 2%–50% in MPV values have been reported [3-5]. Deviations in MPV values have also been reported with other anticoagulants [4, 5]. Differences in the devices used in the measurement can cause deviations of up to 40% in MPV values [5-7]. Since the determination of another platelet parameter, PCT (=platelet count × MPV/10 000), is made by calculation based on MPV values, any factor that negatively affects the measurement of MPV values also negatively affects PCT values. In the study by Peng et al., the time between blood collection and MPV measurement and the devices used in MPV measurement were not specified, thus negatively affecting the reliability of the MPV data and therefore the PCT data of the study. Also, in the study by Peng et al., comparisons were made between pregnants with and without preeclampsia, and the absence of a non-pregnant healthy women group in the comparisons made it difficult to understand whether pregnancy had an effect on the deviations detected in platelet parameters.

Another issue is that it was stated in the discussion section of the article that the change in platelet parameters reflects the decrease in platelet function. The gold standard test used to measure platelet function is light transmission platelet aggregation in platelet-rich plasma, and studies using this method have shown that there is no correlation between platelet aggregation responses and platelet indices such as MPV and PCT [8, 9]. These indices are not considered among the tests showing platelet function and are essentially related to platelet production.

As a conclusion, MPV and PCT values may not be associated with the severity of preeclampsia.

Cengiz Beyan: conception, design, material preparation, data collection, analysis, writing, reading, and final manuscript approval.

The manuscript does not contain clinical studies or patient data.

The author declares no conflicts of interest.