Thimerosal-dependent agglutination complicating the serologic evaluation for unexpected antibodies.

Area of Science:

• Transfusion Medicine
• Immunology
• Clinical Pathology

Background:

• Thimerosal (merthiolate) is a common preservative in blood bank reagents.
• Accurate antibody identification is crucial for safe blood transfusions.

Observation:

• A hospitalized patient exhibited panagglutinins during antibody screening.
• These panagglutinins reacted with all red blood cells tested.
• The patient's serum contained both IgG and IgM antibodies.

Findings:

• The panagglutinins were dependent on the presence of thimerosal.
• Thimerosal-dependent antibodies caused false-positive agglutination reactions.
• Switching to thimerosal-free reagents eliminated the serologic interference.

Implications:

• Clinicians should consider thimerosal-dependent antibodies in cases of unexplained panagglutination.
• Awareness of this phenomenon can prevent transfusion delays and errors.
• Selection of appropriate, preservative-free reagents is vital in specific serologic investigations.