Lab Equipment Calibration SOP Template

1.Purpose

To ensure laboratory instruments are calibrated on schedule against traceable reference standards, so that measurements and test results remain accurate and defensible.

2.Scope

Applies to fixed and portable measuring instruments used for testing, such as analytical balances, pH meters, thermometers, ovens, incubators and spectrophotometers. Pipettes are covered by the pipette calibration SOP.

Definitions

Reference standard

A certified weight, buffer solution or other traceable item used to check an instrument's accuracy.

Tolerance

The acceptable range of deviation from the true value for an instrument to remain in service.

Out of tolerance

A calibration result outside the acceptable range, requiring adjustment, service or removal from use.

3.Responsibilities

Calibration Technician

Performs scheduled calibrations, records results and applies calibration labels.

Lab Analyst

Checks the calibration label before using an instrument and reports suspected drift.

QA Manager

Maintains the calibration schedule, reviews certificates and approves instruments returning to service.

Laboratory Manager

Approves budget for outside calibration service and resolves recurring equipment issues.

RACI matrix

R = Responsible, A = Accountable, C = Consulted, I = Informed

4.Materials and PPE

Materials, tools and systems

• →Certified reference weights, buffers and thermometers
• →Calibration log or CMMS asset register
• →Calibration due-date labels
• →Manufacturer calibration procedures
• →Out-of-service tags

Personal protective equipment

• →Disposable nitrile gloves
• →Lab coat

5.Procedure

1. 5.1

   Review the calibration schedule

   Calibration Technician

   At the start of the week, check the calibration schedule or CMMS asset register for instruments due for calibration and pull them from the bench rotation.

2. 5.2

   Gather reference standards

   Calibration Technician

   Select the certified reference weights, buffer solutions or thermometers required for the instrument, and confirm their certificates have not expired.

   Checkpoint: Reference standards used are within their own certification date.

3. 5.3

   Inspect the instrument before testing

   Calibration Technician

   Check the instrument for physical damage, cleanliness and a stable, level, vibration-free location before starting the calibration procedure.

4. 5.4

   Allow warm-up and stabilization

   Calibration Technician

   Power on the instrument and allow it to warm up and stabilize for the time stated in the manufacturer's instructions before taking readings.

5. 5.5

   Perform the calibration procedure

   Calibration Technician

   Follow the manufacturer's calibration procedure for the instrument type, taking readings at the required points across its measuring range.

6. 5.6

   Record readings and compare to tolerance

   Calibration Technician

   Record each reading against the reference value in the calibration log and compare the deviation to the instrument's stated tolerance.

   Checkpoint: Every reading is recorded before any adjustment is made to the instrument.

7. 5.7

   Adjust or arrange service if out of tolerance

   Calibration Technician

   If a reading falls outside tolerance, adjust the instrument per the manufacturer's instructions and retest, or tag it out of service and arrange vendor repair.

   Warning: Do not return an out-of-tolerance instrument to use until it passes a repeat calibration.

8. 5.8

   Apply the calibration label

   Calibration Technician

   Attach a label showing the calibration date, due date and technician initials to the instrument in a visible location.

9. 5.9

   Update the asset register

   Calibration Technician

   Enter the calibration result, next due date and any parts replaced into the CMMS asset register for the instrument.

10. 5.10

    Notify affected analysts

    Calibration Technician

    Tell the analysts who use the instrument that it is back in service, or that it remains out of service pending repair.

11. 5.11

    Review certificates and trends

    QA Manager

    Review completed calibration certificates for the month, watching for instruments with repeated drift that may need replacement.

12. 5.12

    File the calibration certificate

    QA Manager

    File the signed calibration certificate with the instrument's history file and retain it per the records retention schedule.

6.Quality checks

• →No instrument is used past its calibration due date.
• →Every calibration record shows the reference standard used and its certificate status.
• →Out-of-tolerance instruments are tagged out of service immediately.
• →Calibration certificates are filed and retrievable for every active instrument.

7.Records

• →Calibration log or CMMS asset register
• →Reference standard certificates
• →Calibration certificates
• →Out-of-service tags and repair records

8.KPIs

• →Percentage of instruments calibrated on schedule
• →Number of out-of-tolerance results per quarter
• →Average time an instrument is out of service for repair
• →Number of overdue calibrations

9.Common mistakes

• →Using an instrument past its calibration due date because the label was not checked.
• →Adjusting an instrument before recording the as-found reading.
• →Using an expired reference standard.
• →Not updating the asset register after a vendor repair.

10.Revision history