Abstract
BACKGROUND AND AIMS: Pre-analytical errors in sample collection affect the reliability of blood gas (BG) analysis. Amount of liquid heparin as anticoagulant in samples for BG can affect results by its dilutional direct binding and compositional effects. The aim of this study was to examine the effect of varying amounts of heparin in blood samples on results. MATERIALS AND METHODS: The prospective study was conducted on 15 children at a pediatric intensive care unit (PICU). Three different heparinized syringes were used containing minimal, 60 IU and 120 IU of heparin. A total volume of 1 ml blood in each syringe was taken and was analyzed by blood gas analyzer. Statistical analysis used related samples Friedman's test and Wilcoxon signed ranks test for paired comparisons. The observed bias was also compared with the desirable bias according to specifications by Ricos et al. RESULTS: There was a significant difference (P < 0.05) in values of pH, pCO2, HCO3 (-), Hb and Na(+) in the three syringes. The pCO2, HCO3 (-) and Na(+) levels decreased with the increasing amount of heparin. The observed percentage bias was more than desirable percentage bias specifications for pCO2, HCO3 (-), Hb, Na(+), K(+) and Cl(-) levels. CONCLUSIONS: Syringes with minimal liquid heparin are most appropriate for studying BG parameters as they have the least effect on these parameters. There is a need to standardize the procedure of syringe preparation for BG analysis. Further studies are needed to compare minimal amounts of heparin with commercially available dry balanced heparin syringes.