HEPA Filter
A HEPA (High-Efficiency Particulate Air) filter is an air filtration device that removes at least 99.97% of particles 0.3 microns or larger, used in laminar airflow workbenches and cleanrooms to maintain the sterile environment required for compounding sterile preparations.
Exam Tip
HEPA = 99.97% efficient at 0.3 microns. Certified every 6 months. ISO 5 = inside hood, ISO 7 = buffer room, ISO 8 = ante-area. Critical for sterile compounding under USP 797.
What Is a HEPA Filter?
A HEPA (High-Efficiency Particulate Air) filter is a critical component of sterile compounding environments in pharmacy. It removes airborne particles, bacteria, and fungi from the air supply to create the ultra-clean conditions required by USP 797 for preparing sterile medications.
HEPA Filter Specifications
| Specification | Detail |
|---|---|
| Filtration Efficiency | 99.97% minimum |
| Particle Size | 0.3 microns and larger |
| Standard | DOE standard for HEPA classification |
| Lifespan | Typically 3-5 years (depends on use) |
| Certification | Must be certified every 6 months |
Where HEPA Filters Are Used in Pharmacy
| Equipment | Purpose |
|---|---|
| Laminar Airflow Workbench (LAFW) | Provides ISO 5 air in the direct compounding area |
| Biological Safety Cabinet (BSC) | Protects both product and personnel (hazardous drugs) |
| Compounding Aseptic Isolator (CAI) | Enclosed sterile compounding environment |
| Ceiling HEPA units | Maintains ISO 7 (buffer room) and ISO 8 (ante-area) air quality |
ISO Classifications and HEPA Filtration
| ISO Class | Max Particles (per m3, >=0.5 um) | Pharmacy Area |
|---|---|---|
| ISO 5 | 3,520 | Inside LAFW/BSC (direct compounding area) |
| ISO 7 | 352,000 | Buffer room (cleanroom) |
| ISO 8 | 3,520,000 | Ante-area |
HEPA Filter Maintenance
- Must be certified every 6 months by qualified personnel
- Certification includes DOP (Dioctyl Phthalate) or PAO testing for leaks
- Pre-filters should be changed regularly to extend HEPA filter life
- Damaged HEPA filters must be replaced immediately
Exam Alert
HEPA filters are tested under the Patient Safety and Quality Assurance domain on the PTCE. Know the 99.97% efficiency at 0.3 microns, that certification is required every 6 months, and the ISO classification levels (5, 7, 8) for pharmacy cleanrooms.
Study This Term In
Study guide on MometrixThird-party resources · We may earn a commission from purchases.
ExCPT Study Guide 2026-2027: Complete CPhT Review + 1440 Questions and Detailed Answer Explanations for the NHA Certified Pharmacy Technician Exam (12 Full-Length Exams)
By Test Prep, Newstone
$24.99 · 
Take courses on Udemy
Practice exams on ExamEdge
Study resources on AchievableRelated Terms
USP 795 and USP 797 (Compounding Standards)
USP 795 and USP 797 are United States Pharmacopeia chapters that establish minimum standards for non-sterile compounding (795) and sterile compounding (797), including personnel training, facilities, equipment, and quality assurance requirements.
Aseptic Technique
Aseptic technique is a set of practices and procedures used in sterile compounding to prevent microbial contamination of compounded sterile preparations (CSPs), including proper gowning, hand hygiene, and manipulation within a laminar airflow hood.
Laminar Airflow Workbench (LAFW)
A Laminar Airflow Workbench (LAFW) is a sterile compounding device that uses HEPA-filtered unidirectional airflow to provide an ISO Class 5 environment for preparing sterile preparations such as IV admixtures and ophthalmic solutions.
Your AI study companion · 10 free interactions a day
Stay Updated
Get free exam tips and study guides delivered to your inbox.