Method-specific and unexplained reactivity in automated solid-phase testing and their association with specific...

Area of Science:

• Transfusion Medicine
• Immunology
• Clinical Pathology

Background:

• The detection of antibodies in blood transfusions faces a challenge in balancing sensitivity and specificity.
• No current method perfectly identifies all clinically significant antibodies while excluding insignificant ones.

Purpose of the Study:

• To determine the frequency of unexplained reactivity (UR) and nonspecific reactivity (NS) in solid-phase antibody testing.
• To investigate the persistence of UR and NS and the subsequent development of specific antibodies.

Main Methods:

• A retrospective study analyzed antibody detection tests from a single center over two years.
• Two automated solid-phase instruments were used with a standard three-cell antibody detection test.
• Antibody identification involved solid-phase panels, supplemented with a polyethylene glycol tube method when necessary.

Main Results:

• Of 1905 eligible samples, 52.4% had specific antibodies only, 22.5% had UR only, and 11.9% had both antibodies and UR.
• Nonspecific reactivity was observed in 10.8% of cases (NS only) and 1.3% (Ab and NS).
• Follow-up testing showed specific antibodies replacing UR in 3% of cases and NS in 3% of cases. Persistent UR was noted in six patients, while persistent NS did not develop specific antibodies.

Conclusions:

• Unexplained reactivity and nonspecific reactivity are common findings in solid-phase antibody testing.
• Both UR and NS can persist during follow-up testing.
• Specific antibodies can emerge, sometimes replacing UR, but NS typically does not evolve into a specific antibody.