CSPT Environmental Monitoring and Testing

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)?

Accepted Answer

3,520 particles/m³

Answer

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?

Accepted Answer

Active air sampler (impaction sampler)

Answer

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?

Accepted Answer

1 hour

Answer

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)?

Accepted Answer

0 CFU

Answer

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?

Accepted Answer

DOP/PAO (dispersed oil particulate) aerosol challenge test

Answer

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.

CSPT - Compounded Sterile Preparation Technician Practice Test

CSPT - Compounded Sterile Preparation Technician Practice Test

CSPT Environmental Monitoring and Testing