Rh antigen testing must be done with strict adherence to manufacturer's instructions and a clear understanding of the limitations of the reagents used in the procedure. The table below delineates some of the more commonly seen false-positive reactions with Rh typing reagents and provides insight into the causes and corrective actions that may be undertaken when these problems are presented.
Fibrin interference | Use saline-washed cells; retest |
Rouleaux | Use saline-washed cells; retest |
Bacterial contamination of reagent vial | Open new vial of reagent; retest |
Incorrect reagent selected | Read vial label carefully when repeating test |
Centrifugation too long | Repeat test using shorter centrifugation time, per package insert/SOP |
Modified from Harmening, D: Table 7-10, Modern blood banking and transfusion practices, 6thed, FA Davis, Philadelphia, PA, 2012, p 162.
Fung, MK, Eder, AF, Spitalnik, SL, Westhoff, CM (eds): Technical Manual, 19th ed. AABB, Bethesda, MD, 2017, p 313.