EVALUATION OF PSEUDOTHROMBOCYTOPENIA ON AUTOMATED HEMATOLOGY ANALYZER USING VARIOUS ANTICOAGULANTS

Abstract

Background: Pseudothrombocytopenia (PTCP) is an in vitro artifact primarily caused by anticoagulant-induced platelet clumping, leading to falsely low platelet counts and potential misdiagnosis. Ethylenediaminetetraacetic acid (EDTA) is frequently implicated due to its conformational effects on platelet membrane proteins, exposing hidden epitopes that trigger aggregation. Accurate platelet enumeration is essential for clinical decision-making, and the use of alternative anticoagulants may improve reliability, particularly in patients with suspected PTCP.

Objective: To compare platelet counts and platelet indices among different anticoagulated blood samples using EDTA, Heparin, Sodium Citrate, and Magnesium Sulfate.

Methods: This cross-sectional study included blood samples collected via antecubital venipuncture using strict aseptic techniques. Samples were added to BD Vacutainer tubes containing EDTA, Heparin, Sodium Citrate (3.2%), and custom-prepared Magnesium Sulfate (4.060 mOsmol/mL). All samples were analyzed within one hour using a Sysmex XP-100 three-part hematology analyzer and examined microscopically with Leishman-stained peripheral blood smears. Parameters included platelet count, mean platelet volume (MPV), platelet distribution width (PDW), red blood cell count (RBC), white blood cell count (WBC), and hemoglobin (Hb). Statistical analysis was performed using SPSS version 26. One-way ANOVA and Chi-square tests were applied with p < 0.05 considered statistically significant.

Results: EDTA showed the lowest mean platelet count (92.1 ± 36.3 ×10⁹/L) and the highest MPV (12.0 ± 1.3 fL) and PDW (18.4 ± 3.5 fL), indicating pronounced platelet aggregation. Magnesium Sulfate exhibited the highest mean platelet count (274.4 ± 57.6 ×10⁹/L) with 100.0% of samples in the normal range. Heparin (176.1 ± 55.9 ×10⁹/L) and Sodium Citrate (196.2 ± 60.4 ×10⁹/L) showed intermediate performance. Statistically significant differences were observed across all parameters (p = 0.000).

Conclusion: EDTA significantly underestimates platelet count due to PTCP. Magnesium Sulfate proved to be the most reliable anticoagulant for accurate platelet enumeration, while EDTA remained suitable for RBC and hemoglobin analysis.