Comparison of Full Blood Count Parameters Using Capillary and Venous Samples in Patients Presenting to the Emergency Department

Full blood count (FBC) analysis is a common investigation done in the emergency department (ED). The aim of this study was to determine the accuracy of bedside FBC analysis using capillary blood samples from a finger stab at point of care (POC) compared to a conventional venous blood sample analysis. A total of 314 consecutive patients presenting to the ED were recruited. After consenting, a sample of the patient’s venous (V) blood was obtained via venepuncture and sent to the haematology laboratory for analysis as standard practice. This was followed immediately by collection of a capillary (C) blood sample from a finger stab which was analysed at site using an automated FBC analyser at POC. Agreement between the paired samples for blood parameters including the total white cell count, hemoglobin, and platelet count was assessed by the statistical method of Bland and Altman using V sample as the gold standard. The results showed a statistically significant deviation between capillary and venous samples only for platelet counts (<0.001) and haemoglobin (<0.001). However, the magnitudes of this difference 7.3 × 109/L and 0.5 g/dL respectively, were not clinically significant. The study suggest that the analysis of capillary samples for FBC parameters is a reliable and acceptable alternative to conventional methods with the benefits of being a rapid, convenient, and minimally invasive technique.