Instrument validation is a series of processes through which you test your system to verify or validate the performance specifications published by the manufacturer of the instrument.
Why is it important to validate the instrument?
It is required by the CLIA regulation (CLIA 42 CFR part 493.1253). International sites participate in DAIDS/NIH funded studies, we must be in compliance with the U.S. regulations.
You want to validate the manufacturer’s claims for their method performance characteristics, under your current environmental conditions, e.g. temp, humidity, water, electricity, operator skills etc.
Why validate your instrument?
You want to ensure that the amount of error present in the system won’t affect the interpretation of the test result and compromise patient care.
Ensure that effects of shipment and storage did not affect your instrument performance.
When to validate instrument
- Initial installment of the instrument.
- When a new method or test is implemented.
- When a major part is changed e.g. photometer of a chemistry instrument.
- When an instrument is borrowed.
- When you MOVE your instrument from one location to another.
- Annually (if time allows).
Three validation principles – IQ, OQ, PQ
IQ- Installation Qualification
Installation qualification verifies that the equipment and its subsystems have been installed in accordance to manufacturer’s specifications.
Usually performed by the company’s field representative.
Verification that all components parts are functional
Verification that local supply voltages conform to instrument
Verify that the ambient conditions exist for optimal instrument performance.
Verify correct versions of software were issued with the instrument.
Setting up of instrument parameters (date, time, language, test protoc.
OQ- Operation Qualification
This validation provides evidence that the instrument operates as expected and confirms that installation was successful.
Done by the field representative and lab technicians.
Training of instrument operation.
Testing of controls, calibrators and a few patient samples.
Instrument Validation - PQ
What experiments are performed in Performance Qualification (Method Validation)?
- Precision (Replication)
- Linearity (to verify reportable range)
- Accuracy (correlation or comparison)
- Reference Intervals (Normal values)
- Analytical Sensitivity
- Analytical Specificity
Instrument Validation- Linearity
Linearity or AMR(analytical measurement range) is an assessment of the lowest and highest levels at which an analyte can be accurately measured without any type of dilution or concentration.
It is important to validate the manufacturer’s claims for reportable range of their system/method.
Instrument Validation- Precision
Precision is the degree of reproducibility among several independent measurements of the same sample for the same analyte.
Precision experiment is performed to estimate the imprecision or random error of the analytical method.
Precision is measured in terms of coefficient of variation (CV) and standard deviation (SD). The smaller the CV and SD, the better the precision.
Instrument Validation - Accuracy
A measurement of the exactness of an analytical method, or the closeness of agreement between the measured value and the true value.
Performed to estimate inaccuracy or systematic error of the new method.
Experiment is performed by analyzing forty or more patient samples by the new method (test method) and a comparative method, then estimate the systematic errors on the basis of the differences observed between the two methods.
Reference Range Intervals or NRR
Reference ranges are a measured set of values determined to occur in a healthy nondiseased population.
Why should you validate the manufacturer’s reference intervals or establish your own NRR?
Differences in demographics of your population due to environmental or genetic factors.
Differences in test methods and instruments
Need to write up a validation summary and file together with results data in a binder.
Report should be signed by performing technician and lab Manager/Director or designee.
Submit validation data and summary to Network Lab for approval.