SOP for Finger Dab
1.0 Purpose
To establish a procedure for performing finger dab (finger imprint) tests for monitoring personnel hygiene practices and aseptic conditions in classified areas.
2.0 Scope
This SOP applies to all personnel working in aseptic and controlled areas (Grades A, B, C, and D) where aseptic gowning and aseptic operations are carried out.
3.0 Responsibility
- Microbiology/QC Department: To provide sterile media plates, perform incubation, and record results.
- QA Department: To review and approve results and ensure compliance with cGMP.
- Production/Operators: To comply with sampling requirements and cooperate during finger dab testing.
4.0 Definitions
- Finger Dab/Finger Imprint Test: A microbiological monitoring method where operators press their gloved fingers onto a sterile agar plate to assess potential microbial contamination.
5.0 Materials and Equipment
- Sterile Soybean Casein Digest Agar (SCDA) plates or RODAC plates
- Incubators (20–25 °C and 30–35 °C)
- Sterile marker for labeling
- PPE (sterile gown, sterile gloves, mask, etc.)
6.0 Procedure
6.1 Sampling Frequency
- Perform finger dab sampling of both hands after completion of critical operations or at defined intervals (e.g., post aseptic activity, gowning qualification, or during routine EM).
6.2 Method
- Label agar plates with operator ID, date, area, and time of sampling.
- After completion of activity, ask operator to press the fingertips (all five) of one gloved hand gently onto the surface of the agar plate.
- Repeat with the other hand on a separate plate.
- Avoid excessive pressure to prevent tearing the glove or agar surface.
- Immediately close the plate lid and transfer to the microbiology laboratory in a controlled container.
6.3 Incubation
- Incubate plates at 20–25 °C for 3–5 days for fungal recovery.
- Then incubate at 30–35 °C for 2–3 days for bacterial recovery.
- Record observations daily for microbial growth.
6.4 Interpretation of Results
- Compare results with facility-defined alert and action limits for personnel monitoring based on cleanroom grade (as per ISO 14644 / Annex 1 guidance).
- Typical acceptance criteria (to be customized per facility):
- Grade A/B: <1 CFU per hand (action level ≥1 CFU)
- Grade C: ≤5 CFU
- Grade D: ≤10 CFU
7.0 Precautions
- Ensure sterile handling of media plates.
- Do not touch any non-sterile surface before sampling.
- Record any deviations immediately.
8.0 Documentation
- Record test details in the Personnel Monitoring Logbook.
- Document CFU counts, identification of isolates (if required), and corrective actions in case of excursions.
9.0 References
- EU GMP Annex 1: Manufacture of Sterile Medicinal Products
- USP <1116>: Microbiological Control and Monitoring of Aseptic Processing Environments
- ISO 14644 Cleanroom Standards
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