Enturia

4. Comparison of Chlorhexidine and Tincture of Iodine for Skin Antisepsis in Preparation for Blood Sample Collection

Barenfanger J, Drake C, Lawhorn J, Verhulst SJ. Comparison of chlorhexidine and tincture of iodine for skin antisepsis in preparation for blood sample collection. J Clin Microbiol. 2004;42:2216–2217.

Rationale
Contaminated blood cultures contribute to unnecessary costs and poor patient care, promoting the use of unnecessary antibiotics. Iodine tincture, 5% elemental iodine in ethanol, is frequently used for skin preparation for blood sample collection. Several studies have shown 2% chlorhexidine gluconate (CHG) in 70% isopropyl alcohol (IPA) (ChloraPrep) to have comparable effectiveness to iodine tincture.

Objective
To compare rates of blood culture contamination following patient preinjection skin preparation with ChloraPrep versus iodine tincture.

Design
An observational, retrospective, comparative study of blood culture contamination rates for ChloraPrep versus iodine tincture.

Methods

• At an Illinois medical center, 11,738 blood cultures obtained over two time periods (January 2002 to June 2002, and August 2002 to February 2003) were studied.
  • From January 2002 to June 2002, iodine tincture was used for antiseptic skin preparation
  • From August 2002 to February 2003, ChloraPrep was used for antiseptic skin preparation
• Since contiguous time periods were used for product assessment, a potential bias of seasonality was not accounted for. Therefore, contamination rates for the months of January to June 2003, during which time ChloraPrep alone was used, were included
• Skin was prepared with iodine tincture or ChloraPrep in accordance with the package insert for each product
• Blood cultures were collected by a variety of hospital staff: phlebotomists (who collected about one- third of the samples), emergency department personnel, and nurses.
• During each time period, two in-service education sessions were held in which the importance of skin antisepsis was explained
• For adults, a blood culture consisted of a set of two (aerobic and anaerobic) bottles; a pediatric bottle could be used for children < 18 years of age (approximately 5% of patients)
• A blood culture was considered positive if either one or both bottles grew organisms
• If a patient had more than two cultures taken and only one was positive for coagulase-negative staphylococci, viridans group streptococci, nutritionally deficient streptococci, Peptostreptococcus spp, diphtheroids, or Propionibacterium, Bacillus, or Micrococcus spp, then that culture was considered contaminated
• If a patient had only one culture taken and one of the above-named organisms was present, then data from that culture were discarded

End Point

The primary end point was the occurrence of blood culture contamination.

Results

• ChloraPrep and iodine tincture were associated with comparable rates of blood culture contamination (Table 23)
• At this medical center, ChloraPrep is a cost-effective option (based on cost per unit; 16 cents less per kit than iodine tincture)
• ChloraPrep required 40 seconds less for skin antisepsis than did iodine tincture
• Fourteen phlebotomists and nurses surveyed preferred ChloraPrep, because ChloraPrep was easier, faster, and less costly to use than iodine tincture

Conclusion
Since ChloraPrep has comparable effectiveness to iodine tincture, is cost-effective, and preferred by users, it is an alternative to iodine tincture.

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