CSPT Environmental Monitoring and Testing 1 — Questions and Answers
Question 1: According to USP <797>, what is the maximum permitted total particle count (≥0.5 µm) per cubic meter in an ISO Class 5 primary engineering control (PEC)?
- 3,520 particles/m³ (Correct answer)
- 35,200 particles/m³
- 352,000 particles/m³
- 100,000 particles/m³
Correct answer: 3,520 particles/m³
ISO Class 5 (the classification required for PECs such as laminar airflow workbenches and BSCs) allows no more than 3,520 particles ≥0.5 µm per cubic meter.
Question 2: Which type of sampling device is used to actively collect airborne viable microorganisms for environmental monitoring in a sterile compounding facility?
- Anderson impactor
- Settle plate
- Active air sampler (impaction sampler) (Correct answer)
- Swab contact plate
Correct answer: Active air sampler (impaction sampler)
Active air samplers (e.g., RCS or SAS impaction samplers) draw a known volume of air through the device to quantitatively collect viable particles, providing a volumetric CFU count.
Question 3: A settle plate (passive air sampling) is exposed in a cleanroom. According to USP <797>, how long should a settle plate be exposed to obtain a valid sample in a PEC?
- 15 minutes
- 30 minutes
- 1 hour (Correct answer)
- 4 hours
Correct answer: 1 hour
USP <797> specifies that settle plates should be exposed for no longer than 4 hours, but a standard exposure of 1 hour is typical in ISO Class 5 PECs to obtain meaningful passive air monitoring data.
Question 4: What is the action level for viable surface sampling (contact plates) in an ISO Class 5 PEC, expressed in CFU per contact plate (25 cm²)?
- 0 CFU (Correct answer)
- >1 CFU
- >3 CFU
- >5 CFU
Correct answer: 0 CFU
USP <797> sets the action level for ISO Class 5 surfaces at >0 CFU (i.e., any growth triggers an investigation), because the PEC must be essentially sterile to protect compounded preparations.
Question 5: Which test is performed to verify that a laminar airflow workbench (LAFW) meets ISO Class 5 air quality requirements and that the HEPA filter is intact?
- DOP/PAO (dispersed oil particulate) aerosol challenge test (Correct answer)
- Settle plate culture test
- Endotoxin limulus amebocyte lysate (LAL) test
- Sterility test per USP <71>
Correct answer: DOP/PAO (dispersed oil particulate) aerosol challenge test
DOP or PAO aerosol challenge testing introduces a standardized aerosol upstream of the HEPA filter and measures downstream penetration to verify filter integrity and proper sealing.
Question 6: How frequently must viable environmental monitoring (both air and surface) be performed in ISO Class 5 and ISO Class 7 areas of a Category 2 CSP compounding operation per USP <797>?
- Daily
- Weekly
- Monthly (Correct answer)
- Semi-annually
Correct answer: Monthly
USP <797> requires that viable environmental monitoring of ISO Class 5 and ISO Class 7 areas in Category 2 operations be conducted at least monthly under dynamic (in-use) conditions.
Question 7: When environmental monitoring results exceed established action levels in a sterile compounding cleanroom, what is the FIRST required step?
- Cease all compounding and notify the pharmacist-in-charge immediately
- Increase the frequency of monitoring and document findings
- Identify the source of contamination and perform corrective action before resuming compounding (Correct answer)
- Recall all CSPs compounded in the affected area within the past 30 days
Correct answer: Identify the source of contamination and perform corrective action before resuming compounding
The first mandatory step when action levels are exceeded is to identify the contamination source and implement corrective actions (re-cleaning, re-training, equipment inspection) before compounding can safely resume.
CSPT Environmental Monitoring and Testing 1
According to USP , what is the maximum permitted total particle count (≥0.5 µm) per cubic meter in an ISO Class 5 primary engineering control (PEC)?