Introduction
The Echo 2.0 blood bank analyser is a new method of red cell testing that distinguishes itself with its high automation. The trait allows it to avoid potential human errors, leading to the surfacing of the notion that the technique may be more sensitive than conventional approaches. The idea is the subject of considerable debate, and a substantial body of research has been amassed on the topic. The goal of this literature review is to identify the principles and central traits of each frequently used method, identify different views and controversies, and offer analysis and critique.
Specific and Sensitive Laboratory Testing
Conventional tube technique
The use of antiglobulin tests, also known as Coombs tests after their inventor or the conventional tube technique due to the method employed, dates back more than half a century. It is possible to distinguish two primary varieties: direct, which investigates the patient’s red blood cells (18), and indirect, which works with the patient’s serum (4). The former can be applied to a variety of conditions, as few healthy patients will test positive (14, 24). The latter’s primary purpose is the detection of antibodies in patients (14) and donors (4). The IAT is more commonly performed by other methods, particularly the automated one used by Echo 2.0, and so it is of higher interest to the discussion.
The long history of Coombs tests serves as an indication of their high reliability and utility. With that said, a negative result on the examination does not confirm that there are no issues (12), as while a positive test tends to indicate that a condition is present (5), it can have a low detection rate compared to other methods such as flow cytometry (21), though that result is debatable (22). The primary reason is the lack of sensitivity, with various reagents being unable to detect IgG molecule concentrations below 500 or 150 per cell (20). As such, a need arises for alternate approaches that show higher detection capabilities.
Column agglutination technique
Column agglutination, also known as the gel technique due to the specifics of its execution, may be used for mostly the same purposes as the Coombs test. It is primarily focused on indirect antibody evaluation, but applications that emulate the direct antiglobulin test are possible (7). Some researchers consider column agglutination more sensitive than the conventional tube technique (8), though the conclusion may be debatable. Overall, the method is somewhat well established and sees considerable use in various medical environments.
The supposed higher sensitivity of gel tests compared to their Coombs counterparts is their primary claim to superiority. Some researchers indicate that it shows better results in direct testing (7). There is also evidence available that column agglutination is more sensitive than indirect conventional tube tests (6, 17). However, there is also a considerable body of research that indicates that the two methods are comparable, with minor advantages or disadvantages with regards to a specific testing category (1, 9). There is also research that suggests gel techniques may miss anti-Fyb and -C alloantibodies that are detected by Coombs tests (16). Overall, the two methods complement each other without making either one obsolete.
The automated solid-phase technique (Echo 2.0)
The advances in technology have enabled increased automation and the creation of new approaches that make use of machine precision. Many rely on a refined version of the gel technique, but the company Immucor has introduced a method known as solid-phase red cell adherence assay (2). Speed is a significant advantage of fully automated systems, as they can perform batch testing (3) and operate safely without oversight (11). However, while they are more convenient, their sensitivity is a topic for discussion.
Automated systems often attract praise for their advantages, but they may not be ready to replace human-operated approaches. On the one hand, they can detect anti-Jka antigens that are missed by gel testing (13) and prevent potential danger. Studies show a general sensitivity that is comparable to or greater than that of the other approaches (9, 10, 15). On the other, they can lack precision and display nonspecific results (23), requiring further investigations. In some cases, automated solid-phase techniques can even show false negative tests for patients with known recent positive screens (19). The variety of results suggests that the technology may not be ready to replace its alternatives.
Rationale and Hypothesis
This literature review aims to determine whether there is a consensus in the scholarly literature about the superiority of a specific testing method. The research question is whether the automated solid phase technique is more sensitive than the conventional tube and column agglutination approaches. The hypothesis is that automated systems such as Immucor Echo 2.0 can deliver better results than human-operated alternatives. The study aims to establish an overview of the hierarchy of the three methods listed.
Conclusion
This literature review aims to evaluate the claim that automated solid-phase techniques are more sensitive than other red cell-bound IgG detection methods. It has determined that while they may have some advantages, there are considerable issues that make machine judgments potentially unreliable. As such, automated processes should work alongside human-operated ones to alleviate each other’s weaknesses. Continued future evaluation of various testing systems is necessary as new models become available. A comparative analysis of the specific issues of each method would also be warranted, as they all display considerable general accuracy.
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