How to Determine If a Clinical Reagent Assay Kit Meets the Requirements of the Manufacturer

When purchasing a Clinical Reagent Assay kit, be sure to check the performance and commutability of the materials used. In this article, we discuss problems with within-lot imprecision, the importance of a reagent performance evaluation, and failure to evaluate reagent performance. These problems can be avoided with proper sample handling and a few tips. In this article, we will discuss how to determine if a kit meets the requirements of the manufacturer.

Some Clinical Reagent Assay kits have commutability issues. The reference material may not be as similar to the intended samples as the clinical reagents. These kits may be used to determine the concentration of a substance. Commutability issues can be problematic for a range of analytes. Listed below are some factors that may impact the commutability of Clinical Reagent Assay kits.

The method should be based on clinical decision-making, biological variation, and clinicians' opinions, not on the pharmacological properties of the material. EQA data and current publications on the methodology should demonstrate that reagents are equivalent. The statistical power is typically set at 0.20 to 0.05, and clinical decision points may be similar to the QC levels. If the reagent fails to perform at the clinical decision-making level, the type of failure can be used as a clue as to the nature of the problem.

The commutability issues of clinical reagent assay kits are often difficult to determine, but can be problematic. The problem arises from intrinsic non-commutability. When QC materials are used in clinical trials, the reference standard is not as relevant as the patient specimens. This makes the results of the Clinical Reagent Assay kits inaccurate. The best way to assess commutability is to test a reference reagent against the patient specimens in the same lab.

Problems with within-lot imprecision of reagents

There are numerous issues with within-lot imprecision in clinical reagents. These problems can stem from a variety of sources, including inappropriate storage, transport, and manufacturing processes. Sometimes a manufacturer may make a mistake that leads to imprecision, such as altering the composition or stability of a reagent during production. Other times, a laboratory error is to blame.

Increasing reagent precision is essential in clinical research, but laboratories must also address the resulting problems. Some of the most common causes of within-lot imprecision include reconstitution error, inconsistent lot recovery, and incorrect storage. In addition, incorrect reagent storage can reduce the stability of the reagent. The most common ways to overcome within-lot imprecision are to follow manufacturer guidelines for storage and handling.

In addition to a laboratory's ability to obtain consistent test results, patients' outcomes can be adversely affected by inaccuracy due to within-lot differences. Therefore, laboratory scientists must develop procedures that can quantify the level of variation in a reagent and define the acceptable range for release of patient results. There are several ways to address these problems, including using native patient samples instead of external quality assurance material.

Methods of evaluating reagent performance

The clinical laboratory routinely needs to check the performance of a new reagent lot. The need for this verification can occur at any time, and often on short notice. Therefore, verification protocols must be simple and fast. EP26-A documents these requirements, and provides guidance on how to conduct these tests within the practical constraints of a clinical laboratory. It is the first step in ensuring the quality and consistency of laboratory reagents.

A recent EP26-A document by the Clinical and Laboratory Standards Institute provides guidance on how to assess reagent lot variation. This document identifies a protocol for detecting significant changes in reagent performance after introducing a new lot. For example, an EP26-A-IR document highlights the importance of the consistency of patient samples when introducing a new lot of reagents.