Objective: Molecular testing determines D antigen status when abnormal serologic results are observed. Molecular testing is routinely batched, resulting in longer turnaround time for abnormal D status resolution. During the interim, obstetric patients with questionable/uninterpretable and weak D typing results by serology, per the immunohematology reference laboratory (IRL) policy, will receive RhD negative blood. This study aimed to determine whether serology results achieved a concordance.
Methods: Six hospitals provided samples to the IRL (first IRL) for RhD status by DNA. De-identified samples were sent for serology RhD (second IRL). A concordance of ≥80% was acceptable.
Results: Forty-nine samples were evaluated. Results were concordant (65.3% [32/49]) and discordant (34.7% [17/49]). This is significantly lower than clinically acceptable 80% (z = 2.57, P < .05). The turnaround-time was 3.0 hours for serology and 4.4 days for molecular evaluation.
Conclusion: Due to a low concordance, serology could not be used in place of molecular testing.
Keywords: D-alloimmunization; concordance; immunohematology reference laboratory; molecular; serology; turnaround time.
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