Non-specific red cell reactivity in an obstetric population.

Area of Science:

• Transfusion Medicine
• Immunology
• Obstetrics

Background:

• Antibody screening is crucial in obstetric patients to prevent transfusion reactions and hemolytic disease of the fetus/newborn (HDFN).
• Non-specific red cell reactivity (NSR) can complicate antibody screening interpretation.

Purpose of the Study:

• To investigate the prevalence and characteristics of non-specific red cell reactivity (NSR) during antibody screening in obstetric inpatients.
• To assess the impact of a change in screening methodology on NSR frequency.

Main Methods:

• Observational study of 5438 obstetric inpatients from 2009-2013.
• Review of patient records for NSR, other antibodies, transfusion reactions, and HDFN.
• Comparison of NSR frequency before and after implementation of solid-phase screening in 2011.

Main Results:

• 5.3% of patients had a positive antibody screen, with 1.6% exhibiting NSR.
• NSR was frequently associated with other identifiable antibodies (pre-dating, concurrent, or subsequent).
• The frequency of NSR more than doubled after the transition to solid-phase screening, while specific antibody frequency remained similar.

Conclusions:

• Non-specific red cell reactivity (NSR) is present in 1-2% of obstetric inpatients and its incidence has increased with solid-phase screening.
• While NSR itself may be clinically insignificant, it often co-occurs with clinically significant antibodies and may precede their detection.
• No transfusion reactions or cases of HDFN were associated with NSR in this cohort.