Accuracy and reproducibility of small-volume injections from various-sized syringes

Most of the published studies of potential dosing errors associated with various-sized syringes have involved insulin.1,–5 Some of the earliest studies of insulin administration found decreased accuracy of delivered doses with syringes that had detachable versus nondetachable needles,1,2 leading to the routine use of fixed-needle syringes. Subsequent in vitro and in vivo studies demonstrated inaccuracy when the delivery of small volumes of insulin was evaluated.3,4 Fewer studies have investigated the accuracy of various types of non-insulin syringes with detachable needles. The studies that are available found potential variability in low-dose delivery volumes due to dead space and technical limitations associated with the measurement of small volumes of liquids.6,–8 We hypothesized that if large syringes were used to inject small volumes of medication, the volumes of medication administered would be less accurate and more variable than those administered with smaller syringes. The purpose of this study was to investigate the accuracy and reproducibility of small-volume injections using various-sized syringes.