Quantity of blood inoculated in a needlestick injury from suture needles

We wanted to quantify the amount of blood inoculum present on several commonly used surgical and phlebotomy needles and to determine the effect of single or double gloving, the depth of needle penetration and needle size on inoculum volume. Nineteen, 22 gauge and 25 gauge phlebotomy needles, as well as the tapered suture needles from zero, 3-0 and 5-0 sutures and a cutting needle from a 4-0 suture were assessed. The needles were dipped into blood labeled with 125I-epidermal growth factor and then embedded 2 or 5 millimeters into an agarose gel. The volume of blood inoculum ranged from 133 to 683 nanoliters for the phlebotomy needles and from 35 to 366 nanoliters for the suture needles. Needles were then passed through none, one or two layers of surgical glove material before embedding the needles 5 millimeters into agarose gel. The use of one layer of surgical glove resulted in a significant (p < 0.001) decrease in inoculum from tapered suture needles, but not from the cutting needles. Two gloves were even more efficient (p < 0.001) than one glove at removing blood from all suture needles, including the cutting needle. However, surgical glove material did not significantly reduce the volume of blood inoculum transferred by the phlebotomy needles. The size of the needle and depth of penetration were found to have a significant influence on inoculum.