The Importance of Fingertip Sampling in Quality Assurance

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Quality assurance programs are essential for maintaining the integrity of both processes and products in the pharmaceutical industry. One critical aspect of these programs is fingertip sampling, particularly important in the context of sterile compounding. Here, we explore the history, process, and significance of fingertip sampling in ensuring the safety and efficacy of intrathecal medications.

History of Fingertip Sampling

Pioneering Work of Dr. Lawrence Trissel

Dr. Lawrence Trissel, a renowned expert in chemical testing and stability studies of pharmaceuticals, pioneered the use of fingertip sampling as part of a comprehensive quality assurance (QA) program. In his groundbreaking study, Dr. Trissel examined contamination rates among lab technicians.

  • Initial Study: Two lab technicians were tasked with preparing 100 syringes by drawing up liquid-growth media. These syringes were then tested for contamination, resulting in a 5% contamination rate.
  • Modified Conditions: On a separate occasion, under similar conditions, technicians wiped their hands with alcohol after filling every third syringe. This simple change reduced the contamination rate by 2%, highlighting the importance of frequent hand sanitization.

The Process of Fingertip Sampling

Observational Insights

In a detailed observational study, individuals were seen filling vials with drugs similar to procedures at Hartley Medical. After completing the task, the compounding technician moved to another room where a second technician used a growth plate to capture any bacteria present on the fingertips. This meticulous process is also employed at Hartley Medical to ensure high standards of cleanliness.

Step-by-Step Procedure

  1. Preparation: After compounding, technicians wipe their hands with alcohol.
  2. Sampling: The technician applies their fingertips to a sterile contact agar plate.
  3. Incubation: The plates are incubated for 48-72 hours.
  4. Assessment: The presence of colony-forming units (CFUs) is checked to determine contamination levels.

Why Fingertip Sampling is Important

Assessing Competence and Compliance

Fingertip sampling is an effective method to assess the competence of compounding staff in proper hand-washing and garbing procedures. This practice is essential for ensuring the safety of compounded medications, particularly for sensitive intrathecal drugs.

Industry Guidelines

According to USP-797 guidelines, compounding personnel should have their gloved fingertips assessed semiannually. The procedure involves:

  • Sampling: Obtaining a sample from gloved fingertips using sterile contact agar plates.
  • Testing: Incubating the plates and checking for CFUs.
  • Frequency: Performing fingertip assessments after hand washing and applying sterile gloves at least three times initially before compounding preparations.
  • Results: Ensuring no CFUs are present on the fingertips at the conclusion of each test.


Fingertip sampling is a vital component of quality assurance programs in sterile compounding. The pioneering work of Dr. Lawrence Trissel and ongoing adherence to industry guidelines underscore its importance. At Hartley Medical, we rigorously implement fingertip sampling to ensure the highest standards of cleanliness and safety, ultimately protecting the health and well-being of our patients.