MKT | DOCS | Blog Posts | MV06 How to Plan Your Method Verification: A Step-by-Step Guide for Clinical Labs

Method Verification (MV) is more than a regulatory checklist; it’s a strategic guide to a laboratory’s quality and patient safety. Before diving into calculations, formulas, and metrics - an MV plan needs to be laid out first. Skipping this crucial step makes you more likely to run into gaps that force you to redo the entire process.

While every laboratory is free to customize an MV process, this blog offers a clear, step-by-step general guide to conducting a confident Method Verification:

1️⃣ Define Quality: The Role of Acceptance Criteria and Total Allowable Errors (TEa)

Before starting off with any experiment, a laboratory needs to establish their benchmark on quality requirements. An established quality requirement allows Laboratory Scientists to create a judgement on whether a method is reliable and working according to intended use.

Acceptance Criteria defines the measurable standards and numerical limits that a method needs to be in order to be accepted as suitable for use. These criteria includes the following but is not limited to:

• Type of sample to be used
• Number of samples to be used
• Number of replicates
• Number of days tested
• Maximum Allowable Error (Total Allowable Error, CV%, SD)

Total Allowable Errors (TEa) represents the maximum amount of error considered acceptable without compromising the integrity of a result. By establishing the TEa, a laboratory is able to objectively determine whether the method is reliable by quantitatively comparing experimental results against true values and estimating the amount of error present. If error present falls below the established TEa, then the performance of a method is considered reliable.

While a laboratory is free to define their own quality requirements, regulatory bodies such as Clinical Laboratory Improvement Amendments (CLIA) define standards that can be adopted to ensure reliability is being met.

2️⃣ Select Performance Characteristics: Indicators for Reliability

With the quality requirements selected, the next step is to determine which performance characteristics and experiments are to be tested. Performance characteristics are properties that evaluate how well a method works. Each performance characteristic has their own designated experiment designed to test the method under different working conditions (variation in environment, personnel, reagent, etc.).

By selecting appropriate performance characteristics to be evaluated, a laboratory is able to quantify the amount of errors present which is used to judge the acceptability of the method.

The table below summarizes common performance characteristics and their respective experiments performed to estimate different types of analytical errors:

3️⃣ Perform MV Experiments: Plan Meets Action

Conduct Method Verification experiments and document real-time all crucial performance data. This is the stage where performance parameters from Step 2 are evaluated to determine the reliability of a method. All procedures must be performed with the highest level of precision and accuracy to avoid introducing preventable analytical errors.

To enure regulatory compliance, the verification study should have a structured framework to performing experiments. Regulatory bodies such as Clinical and Laboratory Standards Institute (CLSI) provides a comprehensive guide that can be adopted for laboratory use.

The following table below provides an overview of key performance characteristics and summarizes CLSI guidelines:

4️⃣ Analyze MV Results: Passed/Failed?

After the experiments have been completed, calculate statistical analysis for each experiment to estimate the amount of errors present. Analyze the results by comparing observed errors against a true value or the manufacturer performance claims.

In most cases, TEa serves as the benchmark for acceptance performance. If the experimental errors remain below the TEa threshold, the method is considered as acceptable.

5️⃣ Document the MV: Make Accreditation Easy

The final step is about documentation. When a laboratory seeks to pass accreditation, one of the first thing assessors review is your documentation. A good MV documentation must include the method verification protocol, all experimental results, and any corrective actions implemented during the study. If an MV documentation is organized systematically - evaluation is done quickly with lesser confusion maintaining confidence in results.

REFERENCES

Westgard, James. (2020). Basic Method Validation, 4th Edition. Wisconsin, Westgard QC, Inc.

Genovesi, L. (October 2018). Guide to Method Validation of Test Procedures. Lab Intelligence. Retrieved from: https://www.labcompare.com/354166-Guide-to-Method-Validation-of-Test-Procedures/