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Assessing quality in aseptic compounding


Richard Bateman
BPharm MRPharmS MSc
Quality Assurance Specialist Pharmacist
Pharmacy Department
Guy’s Hospital
E:[email protected]

The risks associated with errors in the preparation of parenteral products have been recognised and documented for many years.

The UK Department of Health has made the reduction of the rates of medication error a prime target within the current NHS modernisation agenda.(1)

Specific areas of concern within this field have been addressed within the UK by the production of practice guidelines and standards. These have included the administration of intrathecal chemotherapy(2) and the safe handling of potassium chloride 15% injection,(3) both of which have been associated with a number of patient fatalities over a period of many years.

The recognition of the risks associated with ward-based preparation of aseptic products have been recognised for a long time, with Breckenridge(4) recommending as far back as 1976 that this practice be brought under the control of pharmacy. The uptake of this advice has been limited, but more recent guidance has reinforced that this principle should still be pursued.(5)

Pharmacy aseptic services have not been without errors, and in the UK a serious incident in 1994 led to a wide-ranging review of many aspects of hospital pharmacy aseptic services. All unlicensed aseptic preparation services are now subject to a regular external audit. This process is coordinated by members of the NHS Pharmaceutical Quality Assurance (QA) Committee. The Committee also publishes detailed guidance on the standards to be met in such facilities.(6)

However, there still remained a lack of data looking at the error rates found when products are made in pharmacy- controlled aseptic compounding units. To address this, the decision was made to run a pilot study to collect data on errors occurring within pharmacy aseptic services. This was coordinated jointly between members of the NHS QA Committee and the Pharmaceutical Aseptic Services Committee (formerly the National CIVAS Group).

Pilot study and results
The aim of this pilot study was to evaluate the type and frequency of occurrence of errors within aseptic processing activities. For the purpose of this study an error was defined as:

“Any occurrence that takes place at any stage of the product preparation process, up to and including storage and distribution, which has the potential to impact on the quality of the product in such a manner that it places the patient receiving the product at risk.”

Data were therefore collected looking at “in-process” errors, in addition to those errors where a product containing an error was released for administration. This was to provide more usable data and to identify areas where there were obvious weaknesses inherent in the processes used in aseptic compounding units. The objectives of the study were defined as follows:

  • To attempt to quantify the number of errors occurring in aseptic services units.
  • To assess consequences for patient safety.
  • To group errors by identifying contributory factors.
  • To identify areas where weaknesses exist in processes.
  • Errors were classified according to:
  • Licensed status of aseptic unit.
  • Product category.
  • Error type.
  • Who detected the error.
  • When the error was detected.
  • Who made the error.
  • Contributory factors.
  • Potential outcome.

Participants were also asked for any brief, relevant comments. If the medication had been administered to a patient, the actual outcome was recorded. If the error was detected before administration, participants were asked to estimate the potential outcome.

Eight pharmacy aseptic units volunteered to take part in the six-month pilot study. Data submitted related to the production of 84,000 doses, and reports were received on 270 errors. This represented 0.32% of processes containing an error. Type and frequency of errors are shown in Figure 1. A breakdown of the data gave the following key facts:

  • 12% errors were classified as moderate.
  • 4% of errors were classified as serious.
  • Percentage error LEAVING pharmacy = 0.008%.
  • Percentage error ADMINISTERED = 0.001%.


Where errors were classified as having serious or moderate potential consequences, the data were further broken down to look at specific and recurring errors. This again highlighted a number of areas where weaknesses in current systems provide potential for error. These included:

  • Selection of incorrect strength of cytotoxic preparation where several are commonly in use.
  • Incorrect cephalosporin used/labelled.
  • Cytotoxic doses supplied on wrong day of regimen.
  • Selection of incorrect IV infusion fluid.

Feedback from participants was very positive, and numerous learning points were highlighted. Several of the reporting categories were clarified to ensure more accurate classification of results. In particular, there was difficulty associated with the classification of severity. To address this issue, a decision was made to adopt the classifications defined in the National Patient Safety Agency document Doing less harm.(7)

The decision was then taken to launch a national voluntary aseptic error-reporting scheme. This is coordinated through the members of the NHS Pharmaceutical QA Committee, and the data are collated centrally. National report summaries are produced every three months, and the data reported back to participants.

The scheme continues to produce valuable data, and current work is looking at differences in some categories seen between the pilot scheme and the national project. Participants can compare their own data with the national figures, and differences in error rates and types can be compared between sites.


  1. Department of Health. An organisation with a memory. London: The Stationery Office; 2000.
  2. Woods K. The prevention of intrathecal medication errors. London: Department of Health; 2001.
  3. NHS National Patient Safety Agency. Patient Safety Alert July 2002.
  4. Department of Health. Breckenridge report. London: DoH; 1976.
  5. A spoonful of sugar. London: Audit Commission; 2001.
  6. Beaney A. The quality assurance of aseptic preparation services. 3rd ed. London: Pharmaceutical Press; 2001.
  7. NHS National Safety Patient Agency. Doing less harm. London: DoH; 2001.

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