Antibody Titers in Transfusion Medicine: A Critical Reevaluation of Testing Accuracy, Reliability, and Clinical Use

Area of Science:

• Clinical immunology
• Medical laboratory science
• Transfusion medicine

Background:

• Antibody titration methods have demonstrated substantial variability since the uniform procedure's introduction in 2008.
• High interlaboratory and intralaboratory variation impacts the reliability of antibody titer results.

Purpose of the Study:

• To assess if recent antibody titration methods reduce interlaboratory and intralaboratory variation.
• To analyze proficiency testing data to quantify assay variability.

Main Methods:

• Proficiency test data from 2014-2018 were analyzed.
• Interlaboratory and intralaboratory variations were compared by method and phase.
• Agreement between laboratories and paired titer results were evaluated.

Main Results:

• Only 54.1% of anti-D and 63.4% of anti-A responses were within 1 titer of the intended result.
• Agreement between laboratories using the same methodology was higher but still showed variability.
• 85% of laboratories using the uniform procedure and 80% using other methods reported a titer difference of 1 or less for consecutive samples.

Conclusions:

• Despite advancements, interlaboratory and intralaboratory variance in antibody titration remains high.
• The reliance on titer results in clinical decision-making needs reevaluation.
• Further improvements in standardization are necessary for reliable antibody titer assessment.