Does Prebiopsy, Nonsterile Ultrasonography Gel Affect Biopsy-Site Asepsis?

The purpose of this study was to determine the extent to which the use of nonsterile gel, prior to antiseptic procedures in ultrasonography (US)-guided percutaneous biopsies, results in contamination of the biopsy site.

Patients referred for US-guided percutaneous biopsies were included in this study. Transmission material used for US evaluation before biopsy-site antiseptic procedures were performed was either nonsterile gel or sterile saline. Patients were randomly assigned to two groups: nonsterile gel (n = 30) and sterile saline (n = 30). Before the transmission material was used and after antiseptic procedures were performed, microbial swabs of a 10-cm²-diameter area were obtained at the biopsy site. Swabs were also obtained from the gel, saline, and povidine-iodine. Inoculated specimen plates were incubated at 37°C under aerobic conditions, and the numbers of colony-forming units recorded. Nominal logistic regression analysis was used to calculate the odds of postantisepsis bacterial growth (after antiseptic procedures were performed) based on group, gender, coincidental disease (diabetes, chronic renal failure, and malignancy), biopsy-site location (head and neck or breast and abdomen), and local factors (skin fold, skin tag, and hair).

The following odds ratios (adjusted for the other variables) and their 95% confidence intervals were calculated: (1) group (2.9 [0.8–11.1]; p = 0.10); (2) gender (1.2 [0.3–5.2]; p = 0.78); (3) coincidental disease (7.6 [0.9–166.7]; p = 0.09); (4) biopsy site location (6.2 [1.4–31.3]; p = 0.02); and (5) local factors (7.0 [1.6–36.0]; p = 0.01). No bacterial growth occurred with swabs obtained from gel, povidine-iodine, or saline.

We conclude that nonsterile gel used prior to percutaneous biopsy does not affect biopsy-site asepsis.