Preanalytical phase: Effects of water ingestion during fasting on routine hematological parameters in a small cohort of young women

Abstract

BackgroundWe analyze the effects of water ingestion before blood extraction on routine hematological parameters. MethodsTwenty female volunteers –mean 24 y– were included. Blood was collected after a 12 h fast period (T0) and 1 h after the ingestion of 300 ml water (T1). These parameters were analyzed: white blood cell (WBC) count; WBC differential count including lymphocytes (LYM), monocytes (MONO), neutrophils, eosinophils (EOS), and basophils; red blood cell (RBC) count; hematocrit (HCT); hemoglobin (HGB); mean cell volume; mean cell hemoglobin; RBC distribution width; and platelet count (PLT). Statistical significance: P < 0.05. Mean difference % (MD%) was calculated for each parameter and was compared with reference change value (RCV). A change was considered clinically significant when MD% exceeded the RCV. ResultsSignificant differences were observed in (medians, T0 vs T1, P): WBC ×109/l (6.51 vs 6.12, 0.002); LYM ×109/l (2.90 vs 2.19, 0.000); MONO ×109/l (0.50 vs 0.48, 0.031); EOS ×109/l (0.17 vs 0.16, 0.003); RBC ×1012/l (4.46 vs 4.40, 0.024); HCT l/l (0.38 vs 0.37, 0.036); HGB g/l (129 vs 129, 0.009). All MDs% were lower than their respective RCV. ConclusionIngestion of 300 ml water 1 h before blood extraction does not alter the hematological parameters studied.