7.4 Calibration, Verification, Validation & Maintenance of Equipment
Key Takeaways
Calibration adjusts an instrument against a traceable standard; verification checks that it still reads within tolerance; validation proves that a process (sterilization, depyrogenation, cleaning) consistently achieves its result; maintenance keeps equipment within its performance limits.
USP <797> requires PECs and classified rooms to be certified initially and at least every 6 months, and a CVE, BSC or CACI used for presterilization steps is also certified at least every 6 months.
Temperature, humidity and pressure monitoring devices are calibrated or verified as the manufacturer recommends, or every 12 months if no interval is given.
Steam and dry heat sterilization are verified with biological indicators with every run or load, and depyrogenation cycles with endotoxin challenge vials initially and at least annually.
When equipment is found out of tolerance, it is taken out of service and repaired or recalibrated, and the CSPs made since the last acceptable check are assessed. All of this is documented, as USP <797> Section 20 requires.
7.4 Calibration, Verification, Validation & Maintenance of Equipment
Every measurement a compounding pharmacist relies on comes from equipment: particle counts, pressure readings, delivered volumes, weights, incubation temperatures, sterilizer cycles. If that equipment is off, the data are wrong, and a CSP can look acceptable when it is not. The BCSCP outline (task 1A8) expects you to design and supervise the program that keeps every instrument trustworthy.
Four terms that exams mix up
| Term | Meaning | Example |
|---|---|---|
| Calibration | Comparing an instrument with a traceable standard and adjusting it, documenting the before and after values | A service technician calibrates a balance with certified weights |
| Verification | Checking that an instrument or process still performs within tolerance, without adjusting it | Daily balance check with a test weight; daily ACD accuracy check |
| Validation | Documented evidence that a process consistently produces the intended result | Proving an autoclave cycle sterilizes a defined load; proving a depyrogenation cycle gives a 3-log endotoxin reduction |
| Maintenance | Preventive and corrective work that keeps equipment within its limits | Replacing ACD pump tubing on schedule; replacing a HEPA filter |
For sterilizers and similar equipment, validation is often organized as installation qualification (IQ), operational qualification (OQ) and performance qualification (PQ). IQ shows the equipment is installed correctly, OQ that it works across its operating ranges, and PQ that it performs the real process on real loads.
Master table of checks and intervals
| Equipment or process | Requirement | Source |
|---|---|---|
| PECs and classified rooms | Certified initially, then at least every 6 months: airflow, HEPA leak test, total particle count under dynamic conditions, smoke pattern tests. Also after redesign, construction, PEC replacement or relocation, or changes affecting airflow. The designated person reviews every report | USP <797> 5 |
| CVE, BSC or CACI used for presterilization weighing | Certified at least every 6 months | USP <797> 4.2.6 |
| Laminar airflow systems and robotic enclosures | Dynamic smoke test initially and at least every 6 months | USP <797> 4.2.3 |
| Pressure-differential monitors | Monitor continuously; results reviewed and documented daily on compounding days; calibrated or verified per manufacturer or every 12 months | USP <797> 4.2.5; FAQ |
| Temperature and humidity devices (rooms, storage, refrigerators) | Calibrated or verified per manufacturer, or every 12 months if unspecified | USP <797> 9.3.4, 19.1 |
| Automated compounding devices | Accuracy assessed before first use and each day used; daily record; corrective action if out of specification | USP <797> 9.1 |
| Balances | Checked per SOP (commonly daily) with test weights; periodic calibration; must meet USP <41> repeatability and accuracy | USP <41>, <1251> |
| Impaction air samplers | Serviced and calibrated as the manufacturer recommends | USP <797> 6.1 |
| Incubators | Temperature monitored and documented throughout incubation; located outside the sterile compounding area | USP <797> 6.2.2, 6.3.2 |
| Steam sterilizer | Biological indicators (for example Geobacillus stearothermophilus) with each run or load; calibrated recorder for each cycle; steam from water meeting the manufacturer's specification; run and load numbers in the compounding record | USP <797> 10.3 |
| Dry heat sterilizer | Biological indicators (Bacillus atrophaeus) with each run or load; calibrated recorder; even heat distribution | USP <797> 10.4 |
| Depyrogenation oven | Effectiveness shown initially and at least annually with endotoxin challenge vials (at least a 3-log reduction); re-established after changes to load, time or temperature | USP <797> 10.1 |
| Sterilizing filters | Integrity test (such as bubble point) after each use | USP <797> 10.2 |
| Growth media | Supplier COA for commercial media; growth promotion testing of each in-house batch | USP <797> 2.3 |
Out-of-tolerance findings
When a check fails, for example a balance reading 0.3% high on its daily test weight, the response follows a set pattern:
- Take the equipment out of service and label it.
- Assess the impact. Identify the CSPs made with it since the last acceptable check and judge whether their quality could have been affected. Quarantine or recall them under the SOPs if necessary.
- Repair or recalibrate, then verify before returning the equipment to service.
- Document the finding, the impact assessment and the corrective action, and look for trends.
This is why daily verification pays off. It limits how far back you have to look when something goes wrong.
Maintenance and servicing
- Equipment used in classified areas stays there except for calibration, servicing or cleaning. When it comes back, it is cleaned and wiped with sterile 70% IPA or a suitable disinfectant.
- Servicing facilities or equipment triggers microbiological air and surface sampling. That includes changing HEPA filters in the ceiling or the PEC; routine prefilter changes usually do not trigger it.
- Preventive maintenance schedules, such as ACD tubing changes, sterilizer gaskets and HEPA filter replacement plans, come from the manufacturer's instructions and belong in the SOPs.
Records
USP <797> Section 20 requires records of equipment calibration, verification and maintenance, along with certification reports and any corrective actions for failures. Inspectors often look at these first, because gaps show quickly.
A pharmacy's refrigerator temperature monitor comes with no manufacturer-recommended calibration interval. Under USP <797>, how often must it be calibrated or verified for accuracy?
Every 12 months
Every 3 months
Only when it alarms
Every 5 years
How often does USP <797> require the effectiveness of steam sterilization of CSPs to be verified with biological indicators?
Once, when the autoclave is installed
Every 6 months, at facility certification
With each sterilization run or load
Only when a sterility test fails
At the morning check, a balance used to weigh nonsterile API for Category 2 CSPs reads 0.3% high on its certified test weight, well outside tolerance. It passed the previous morning. What is the best response?
Keep using it and correct each weight by 0.3% by hand
Take it out of service, assess the CSPs weighed on it since the last acceptable check, have it repaired or recalibrated and verified, and document everything
Keep using it, because the error is below 1%
Recalibrate it at the next 6-month facility certification
Sections you finish are checked off in the contents.