yemenjmedYemen Journal of MedicinecoVolume 4 Issue 2MultidisciplinaryEnglishMay-August 2025NNY20250922ArticleK₂EDTA Versus K₃EDTA Stability in Yemeni Laboratories: Toward Climate-Adapted Protocols for Resource-Limited SettingsEnglishY372378Naif Taleb Ali¹EnglishN²EnglishY10.63475/yjm.v4i2.0150Background: Preanalytical variability due to anticoagulant choice remains inadequately characterized in resource-limited tropical settings like Yemen, where environmental stressors exacerbate challenges. This study aimed to compare the stability and cost-effectiveness of K₂EDTA and K₃EDTA anticoagulants for complete blood count testing under simulated Yemeni conditions. Methods: Prospective study of 100 healthy adult male volunteers in Ad’Dla Governorate, Yemen (January–March 2025). Paired samples in K₂EDTA/K₃EDTA tubes were analyzed at baseline (T0) and after 6-hour storage at 22 ± 2°C (T6). Statistical analysis included Bonferroni-corrected repeated-measures ANOVA and paired t-tests. Results: Fresh samples showed high inter-anticoagulant concordance (ICC > 0.90). After 6-hour storage, K₂EDTA exhibited significant Mean Corpuscular Volume (MCV) reduction (Δ = −2.33 fL, p < 0.001; Cohen’s d = 0.42), while K₃EDTA showed greater Red Blood Cell (RBC) instability (Δ = −0.16 × 10¹²/L, p = 0.008). An observed bidirectional Red Cell Distribution Width – Standard Deviation (RDW-SD) pattern emerged: K₂EDTA increased values (+1.71%) while K₃EDTA decreased them (−2.20%, both p < 0.01). K₃EDTA offered 4.7% direct cost savings per test but incurred higher slide-review costs due to 8% platelet clumping. Conclusions: K₂EDTA demonstrates superior stability for delayed processing (> 2 hours), while K₃EDTA is preferable for immediate analysis. These findings provide preliminary guidance for hematology testing in Yemeni laboratories and similar tropical settings, pending validation in diverse populations and extreme conditions.EnglishPreanalytical variability, EDTA anticoagulants, Sysmex KX-21N, resource-limitedsettings, Yemen, tropical hematology, Yemeni laboratorieshttps://www.yemenjmed.com/admin/abstract?id=227References1619