Incompatible crossmatch following nonreactive antibody detection test. Frequency and cause

Area of Science:

• Transfusion Medicine
• Immunology
• Clinical Pathology

Background:

• Blood crossmatching is critical for preventing transfusion reactions.
• Unexpected incompatible crossmatches after a nonreactive antibody screen pose a diagnostic challenge.

Purpose of the Study:

• To determine the frequency and causes of incompatible crossmatches following nonreactive antibody detection tests.
• To analyze when these incompatibilities are detected during the crossmatching process.

Main Methods:

• Retrospective review of 261,136 crossmatches from 116,278 patient samples.
• Identification of patients with incompatible crossmatches despite a nonreactive antibody detection test.
• Serologic evaluation to determine the cause of incompatibility.

Main Results:

• 101 patients had incompatible crossmatches after a nonreactive antibody screen.
• The cause was identified in 69 patients; 52% were detected only after 37°C incubation and/or the antiglobulin phase.
• 33% of incompatibilities were detected earlier (immediate spin/room temperature), while the cause remained unidentified in 16 patients.

Conclusions:

• A significant proportion of incompatible crossmatches occur despite initial nonreactive antibody screens.
• Many of these late-detected incompatibilities require advanced serologic testing phases (37°C incubation, antiglobulin phase).
• Further investigation is needed for unidentified incompatibilities to ensure transfusion safety.