Effect of preanalytical and analytical variables on the clinical utility of mean platelet volume.
Author(s): Buttarello M, Mezzapelle G, Plebani M
Publication: Clin Chem Lab Med, 2018, Vol. 56, Page 718-725
PubMed ID: 29194040 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of patient sex and age, use of sodium citrate blood rather than K2EDTA blood, and delayed analysis on platelet parameters. The relationship between mean platelet volume (MPV), platelet count, and plateletcrit (PCT) was also investigated.
Conclusion of Paper
Blood from women had higher mean platelet counts and PCT and lower mean MPV and platelet-large cell ratio (P-LCR) than that from men but no significant effects of patient age were found. Specimens stored at room temperature for 4 h before analysis rather than analyzed after 30 min had higher mean platelet count, MPV, platelet distribution width (PDW), P-LCR, and PCT. There was an inverse nonlinear correlation between MPV and platelet count and a positive relationship between PCT and platelet counts.
When analyzed 15 min after collection, MPV was lower in sodium citrate blood than K2EDTA blood. Significantly higher MPVs were noted at 30 min compared to 15 min for sodium citrate blood stored at room temperature and K2EDTA blood stored at 4˚C and at 1 h in K2EDTA blood stored at room temperature. When stored for 8 h or more in K2EDTA tubes, the increases were greater at room temperature than at 4˚C. After the initial 30 min, MPV changed more rapidly in EDTA tubes than sodium citrate tubes. Interestingly, MPV declined below that analyzed within 15 min when stored for more than 2 h in sodium citrate tubes.
Studies
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Study Purpose
This study investigated the effects of patient sex and age and delayed analysis on platelet parameters and investigated the relationship between MPV and platelet counts. Blood was collected from 170 healthy subjects (ages 18-76) after overnight fast into 3 mL K2EDTA tubes and analyzed within 30 min and again after 4 h. Precision was evaluated by reanalysis of three specimens nine times, representing different MPV in different batches at 15 min intervals. To investigate the relationship between MPV and platelet concentration, additional blood was collected from 331 in-patients (diagnosis unspecified) and analyzed 3-4 h after collection. All platelet variables were measured on a hematology auto-analyzer.
Summary of Findings:
Blood from women had higher mean platelet counts (240 vs 219, P<0.0001) and PCT (0.26 versus 0.24, P<0.0001) and lower mean MPV (10.5 versus 10.7, P=0.0003) and P-LCR (29.7% versus 31.4%, P=0.0005) than that from men but no significant effects of patient age were found. Specimens stored at room temperature for 4 h before analysis had higher mean platelet counts (240 versus 231, P<0.0001), MPW (11.1 versus 10.6, P=0.0001), PDW (13.5 versus 12.7, P=0.0003), P-LCR (33.1 versus 30.8, P<0.0001), and PCT (0.28 versus 0.25, P<0.0001) compared to blood analyzed after 30 min. Importantly, the CV of MPV from specimens analyzed nine times was only 0.8%, which is negligible compared to the changes observed with delayed analysis. There was an inverse nonlinear correlation between MPV and platelet count using specimens from in-patient and healthy individuals (statistics not presented). As expected, a stronger relationship between PCT and platelet count was present than that between PCT and MPV. The authors note that division of platelet count into tertiles results in different MPV ranges.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Not specified
- Normal
Platform:
Analyte Technology Platform Cell count/volume Hematology/ auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Patient age <45 years
46-65 years
>65 years
Storage Storage duration 30 min
4 h
Preaquisition Patient gender Male
Female
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Study Purpose
This study investigated the effects of storing blood in K2EDTA tubes at room temperature and 4˚C and in sodium citrate tubes at room temperature on MPV. Blood was collected from 20 healthy individuals into K2EDTA and sodium citrate tubes. Specimens were stored in K2EDTA tubes at room temperature and 4˚C and in sodium citrate tubes at room temperature for 15 min, 30 min, 1 h, 1.5 h, 2 h, 3 h, 4 h, 8 h, 12 h, and 24 h before analysis. MPV was determined on a hematology auto-analyzer.
Summary of Findings:
When analyzed 15 min after collection, MPV was lower in sodium citrate blood than K2EDTA blood. Significantly higher MPVs were noted at 30 min compared to 15 min for sodium citrate blood stored at room temperature (P=0.0024) and K2EDTA blood stored at 4˚C (P=0.006) and at 1 h in K2EDTA blood stored at room temperature (P<0.0001). The increases were greater at room temperature than at 4˚C when stored for 8 h or more in K2EDTA tubes. After the initial 30 min, MPV changed more rapidly in EDTA tubes than sodium citrate tubes. Interestingly, MPV declined below that analyzed within 15 min when stored for more than 2 h in sodium citrate tubes.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Cell count/volume Hematology/ auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Anticoagulant Sodium citrate
Potassium EDTA
Storage Storage temperature 4˚C
Room temperature
Storage Storage duration 15 min
30 min
1 h
1.5 h
2 h
3 h
4 h
8 h
12 h
24 h