Effect of iodophor vs iodine tincture skin preparation on blood culture contamination rate

Objective.

—To determine if iodine tincture is a more effective skin antiseptic for blood culture collection than povidone-iodine, an iodophor.

Design.

—Pairwise comparisons across phases. In phases 1 and 3, blood culture skin preparation was performed with the iodophor; in phases 2 and 4, skin preparation was performed with iodine tincture.

Setting.

—Emergency department of a large urban teaching hospital.

Patients.

—All adult patients seen in the emergency department who had blood cultures collected because a systemic bacterial infection was suspected.

Main Outcome Measure.

—The blood culture contamination rate for the iodophor and iodine tincture skin preparations.

Results.

—A total of 8467 blood cultures were collected during the study, and 421 (4.97%) were classified as contaminated. The contamination rate for the blood cultures collected using the iodophor was 6.25%, and the contamination rate for the cultures using iodine tincture was 3.74%; this difference is statistically significant (P<.00001).

Conclusions.

—The effectiveness of the skin antiseptic may be an important factor in determining contamination rate in blood culturing. If these results are confirmed by others, then institutions that have a high blood culture contamination rate when using an iodophor for skin preparation should consider changing to iodine tincture. (JAMA. 1993;269:1004-1006)