Purpose: Platelet Indices (PI) like mean platelet volume (MPV), platelet distribution weight (PDW) and plateletcrit can be measured by hematology analyzers. The purpose of this study was to evaluate the effect of the time delay between sampling and testing to the PI values with Mindray BC-5800 analyzer.

Material and Methods: Complete blood counts were measured from blood samples collected in K3- EDTA tubes with Mindray BC-5800 (Mindray BioMedical Electronics Co., Ltd., Shenzhen, China) device. Values obtained from 45–60 min after blood collection was accepted as basal values. CBC was done on the samples after 150 and 270 minutes and 24 hours. The stability of the TI parameters was determined by comparing the results to the basal sample.

Results: Platelet count remained unchanged with storage. PDW were higher in 24 hours compared to the basal level The difference of PDW levels between the measurements at baseline and stored at room temperature for 24 hour (p<0.005) (percent change 7.9%) and, MPV, P- LCR and P-LCC values were increased gradually over basal value (p<0.01).

Conclusion: Storage of EDTA blood resulted in a progressive increase in the TI results with Mindray BC-5800 therefore it is better to standardize the time delay between sampling and analysis.