Picture an auditor pointing at a balance in your QC lab and asking, "When was this last checked, and by whom?"
If the answer means flipping through notebooks, the instrument may be fine, but the paperwork isn't. Audit-ready means you can show the proof in under a minute.
Here's how a pharma QC lab could set that up, using the two instruments that run all day: the balance and the pH meter.
Start with One Instrument Register
Keep a single, current list of every balance and pH meter. For each one, record:
- A unique ID and its location.
- The last calibration date and the next due date.
- Who calibrated it and which standards were used.
- Its status: in use, under service or out of use.
Label every instrument with its ID and due date, so anyone can check at a glance.
Set a Rhythm: Daily, Periodic, Service
- Every day or every use: verify the balance with a check weight and calibrate the pH meter with fresh buffers.
- At set intervals: carry out full calibration against certified standards.
- On schedule: arrange preventive maintenance by a qualified engineer.
Your SOPs and the standard your lab follows decide the exact limits and intervals. The point is to write them down and stick to them.
Balances: Check Where You Weigh
- Use certified reference weights with traceable certificates.
- Test across the range you actually use, not just one point.
- Keep the balance level, clear of draughts and away from vibration.
- Record the reading and the tolerance every time.
pH Meters: Fresh Buffers, Healthy Electrodes
- Use fresh, in-date buffers that bracket your sample range.
- Never pour used buffer back into the bottle.
- Rinse the electrode between solutions and store it in the recommended solution.
- Track electrode response over time. A slow decline tells you to replace it before it fails.
If the meter won't calibrate, stop and fix it before testing any samples.
Records That Stand Up to Scrutiny
Many labs follow the ALCOA principles: records should be attributable, legible, contemporaneous, original and accurate. In practice, that means signing and dating each entry at the time, never backfilling, and filing certificates alongside the register.
When an Instrument Fails a Check
- Stop using it and tag it "Out of Service."
- Log the failure and tell the supervisor.
- Review results produced since the last good check.
- Fix, recalibrate and verify before it returns to use.
Having this written down means no panic when it happens.
A Five-Minute Pre-Audit Walk-Round
- Does every instrument carry a visible ID and an in-date label?
- Do the register and the certificates agree?
- Are today's checks recorded?
- Are reference weights and buffers in date and stored properly?
- Can staff explain what they do when a check fails?
The Right Kit Makes It Easier
At LIFORAMED, our laboratory range includes electronic balances with auto-calibration and benchtop pH meters with automatic temperature compensation, plus indicators and glassware that support dependable measurements. Our guide on why calibration matters covers the basics behind balances, pH meters and spectrophotometers.
Want help choosing instruments or planning upkeep so they stay accurate? Get in touch with our team.