Best Practice #6 (ARCHIVED) FAQ

Best Practice #6: Eliminate glacial acetic acid from all areas of the hospital.

1. Question: Our laboratory and pathology departments use small quantities of glacial acetic acid to prepare tissue fixatives, such as "Clarke's Solution" (75 mL of absolute ethanol, with 25 mL of glacial acetic acid to be prepared immediately before use). We are not aware of a substitute that can be used for this purpose. The laboratory also uses a dilute acetic acid for urinalysis and electrophoresis. What are your recommendations for this best practice in light of this information?

Answer: A footnote with this Best Practice notes that laboratory use is excluded if the lab purchases the product directly from an external source. This provision is provided because there may be instances in which laboratories or research areas need extremely toxic chemicals. In such cases, it is critical to store and use these products, including glacial acetic acid, only in these areas. Take precautions to ensure that glacial acetic acid is never available in patient care areas of the hospital or in the pharmacy.

If glacial acetic acid must be used in the laboratory or research area, follow these recommendations:

• The laboratory/research area must order the product directly and store it exclusively in the laboratory/research area.

• Glacial acetic acid should be purchased in the smallest quantity and container size that will meet the needs of the laboratory/research area, and the product should be stored according to Occupational Safety and Health Administration (OSHA)/National Institute of Occupational Safety & Health (NIOSH) recommendations.

• Access to storage locations should be limited to only those personnel who have a legitimate need for the chemical. In addition, reminders at storage locations and other appropriate places should direct employees to never provide glacial acetic acid to another department.

• If the laboratory/research area must use central supply/materials management to order glacial acetic acid and cannot order it directly, the order entry screen in the purchasing system should include a warning: “For Laboratory Only–Do Not Provide to Other Areas.” Once the product is received in central supply/materials management, it should be delivered immediately. All glacial acetic acid should be stocked in the laboratory/research area and not in central supply/materials management. The pharmacy should never order, stock, or distribute glacial acetic acid.

^{Rev. 3/26/2014}

2. Question: Intra-operative topical use of modified Carnoy's solution, which is prepared using glacial acetic acid, is used following resection of keratocystic odontogenic tumors.¹ The original Carnoy's formula is still available from a chemical supply manufacturer, but it contains chloroform. The US Food and Drug Administration (FDA) no longer allows the use of chloroform in any therapeutic agent. What do you suggest in this case?

Answer: In rare circumstances when pharmacy needs to prepare a solution using glacial acetic acid, the pharmacy should obtain the needed amount of glacial acetic acid from the laboratory, prepare the needed amount of modified Carnoy’s solution, and immediately return any remaining glacial acetic acid to the laboratory.

_Reference

1. Progel MA. The keratocystic odotogenic tumor. Oral Maxillofac Surg Clin North Am. 2013;25(1):21-30.

^{Rev. 3/26/2014}